How to find the diagonal of a cube - Math
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What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
What is the length of the diagonal of a cube with a volume of
? Round to the nearest hundredth.
What is the length of the diagonal of a cube with a volume of
? Round to the nearest hundredth.
First, you need to find the side length of this cube. We know that the volume is:
, where
is the side length.
Therefore, based on our data, we can say:

Solving for
by taking the cube-root of both sides, we get:

Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:
(Note that not all points are drawn in on the cube.)

The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
First, you need to find the side length of this cube. We know that the volume is:
, where
is the side length.
Therefore, based on our data, we can say:
Solving for by taking the cube-root of both sides, we get:
Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:
(Note that not all points are drawn in on the cube.)

The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
What is the length of the diagonal of a cube with a surface area of
? Round your answer to the nearest hundredth.
What is the length of the diagonal of a cube with a surface area of
? Round your answer to the nearest hundredth.
First, you need to find the side length of this cube. We know that the surface area is defined by:
, where
is the side length. (This is because the cube is
sides of equal area).
Therefore, based on our data, we can say:


Take the square root of both sides and get:

Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
First, you need to find the side length of this cube. We know that the surface area is defined by:
, where
is the side length. (This is because the cube is
sides of equal area).
Therefore, based on our data, we can say:
Take the square root of both sides and get:
Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
Suppose the volume of a cube is
. What is the length of the diagonal?
Suppose the volume of a cube is . What is the length of the diagonal?
Write the equation for the volume of a cube. Substitute the volume to find the side length,
.



Write the equation for finding diagonals given an edge length for a cube.

Substitute the side length to find the diagonal length.
The answer is
.
Write the equation for the volume of a cube. Substitute the volume to find the side length, .
Write the equation for finding diagonals given an edge length for a cube.
Substitute the side length to find the diagonal length.
The answer is .
Compare your answer with the correct one above
Find the diagonal of a cube with a side length of
.
Find the diagonal of a cube with a side length of .
The diagonal of a cube is simply given by:

Where
is the side length of the cube.
So since our 


The diagonal of a cube is simply given by:
Where is the side length of the cube.
So since our
Compare your answer with the correct one above
Find the length of a diagonal of a cube with volume of 
Find the length of a diagonal of a cube with volume of
There is a formula for the length of a cube's diagonal given the side length. However, we might not remember that formula as it is less common. However, we can also find the length using the Pythagorean Theorem.
But first, we need to find the side length. We know the volume is 64. Our formula for volume is

Substituting gives

Taking the cube root gives us a side length of 4. Now let's look at our cube.

We need to begin by finding the length of the diagonal of the bottom face of our cube (the green segment). This can be done either by using the Pythagorean Theorem or by realizing that the right triangle is in fact a 45-45-90 triangle. Either way, we realize that our diagonal (the hypotenuse) is
.

We now seek to find the diagonal of the cube (the blue segment). We do this by looking at the right triangle formed by it, the left vertical edge, and the face diagonal we just found. This time our only recourse is to do the Pythagorean Theorem.




In general, the formula for the diagonal of a cube with side length
is

The length of our diagonal is 
There is a formula for the length of a cube's diagonal given the side length. However, we might not remember that formula as it is less common. However, we can also find the length using the Pythagorean Theorem.
But first, we need to find the side length. We know the volume is 64. Our formula for volume is
Substituting gives
Taking the cube root gives us a side length of 4. Now let's look at our cube.

We need to begin by finding the length of the diagonal of the bottom face of our cube (the green segment). This can be done either by using the Pythagorean Theorem or by realizing that the right triangle is in fact a 45-45-90 triangle. Either way, we realize that our diagonal (the hypotenuse) is .

We now seek to find the diagonal of the cube (the blue segment). We do this by looking at the right triangle formed by it, the left vertical edge, and the face diagonal we just found. This time our only recourse is to do the Pythagorean Theorem.
In general, the formula for the diagonal of a cube with side length is
The length of our diagonal is
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If the volume of a cube was one eighth, what is the diagonal of the cube?
If the volume of a cube was one eighth, what is the diagonal of the cube?
Write the volume of a cube and substitute the given volume to find a side length.



Write the diagonal formula for a cube and substitute the side length.

Write the volume of a cube and substitute the given volume to find a side length.
Write the diagonal formula for a cube and substitute the side length.
Compare your answer with the correct one above
If the volume of a cube was
, what is the length of the diagonal?
If the volume of a cube was , what is the length of the diagonal?
Write the equation for finding the volume of a cube, and substitute in the volume.



Write the diagonal equation for cubes and substitute in the given length.

Write the equation for finding the volume of a cube, and substitute in the volume.
Write the diagonal equation for cubes and substitute in the given length.
Compare your answer with the correct one above
If the surface area of a cube was
, what is the length of the diagonal?
If the surface area of a cube was , what is the length of the diagonal?
Write the surface area formula for cubes and substitute the given area.




Write the diagonal formula for cubes and substitute the side length.

Write the surface area formula for cubes and substitute the given area.
Write the diagonal formula for cubes and substitute the side length.
Compare your answer with the correct one above
Find the distance from point A to point B in the cube below (leave answer in simplest radical form):

Find the distance from point A to point B in the cube below (leave answer in simplest radical form):

When calculating the diagonal of the cube, point A to point B.
We must first find the diagonal of the base of the cube.
The base of the cube is a square where all sides are 8.
The diagonal of this square is found either by the pythagorean theorem or by what we know about 45-45-90 triangles to get the diagonal of the base below:

The diagonal of the base would be from point A to point C in the drawing.

We can see that the diagonal of the base and side BC of the cube form the two legs of a right triangle that will allow us to find the 3D diagonal of the whole cube.
Use the pythagorean theorem with BC and the Diagonal of the Base.



Take the square root of both sides.

After simplifying everything we get the final answer for the Diagonal of the Cube (AB).

When calculating the diagonal of the cube, point A to point B.
We must first find the diagonal of the base of the cube.
The base of the cube is a square where all sides are 8.
The diagonal of this square is found either by the pythagorean theorem or by what we know about 45-45-90 triangles to get the diagonal of the base below:
The diagonal of the base would be from point A to point C in the drawing.

We can see that the diagonal of the base and side BC of the cube form the two legs of a right triangle that will allow us to find the 3D diagonal of the whole cube.
Use the pythagorean theorem with BC and the Diagonal of the Base.
Take the square root of both sides.
After simplifying everything we get the final answer for the Diagonal of the Cube (AB).
Compare your answer with the correct one above
A cube has a side length of 6 meters. What is the length of its diagonal across one of the faces?
A cube has a side length of 6 meters. What is the length of its diagonal across one of the faces?
Since all sides of a cube are equal and all sides form right angles, we use pythagorean theorem to find the length of the diagonal.



meters
Since all sides of a cube are equal and all sides form right angles, we use pythagorean theorem to find the length of the diagonal.
meters
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Find the length of the diagonal connecting opposite corners of a cube with sides of length
.
Find the length of the diagonal connecting opposite corners of a cube with sides of length .
Find the diagonal of one face of the cube using the Pythagorean Theorem applied to a triangle formed by two sides of that face (
and
) and the diagonal itself (
):





This diagonal is now the base of a new right triangle (call this
). The height of that triangle is an edge of the cube that runs perpendicular to this diagonal (call this
). The third side of the triangle formed by
and
is a line from one corner of the cube to the other, i.e., the cube's diagonal (call this
). Use the Pythagorean Theorem again with the triangle formed by
,
, and
to find the length of this diagonal.






Find the diagonal of one face of the cube using the Pythagorean Theorem applied to a triangle formed by two sides of that face ( and
) and the diagonal itself (
):
This diagonal is now the base of a new right triangle (call this ). The height of that triangle is an edge of the cube that runs perpendicular to this diagonal (call this
). The third side of the triangle formed by
and
is a line from one corner of the cube to the other, i.e., the cube's diagonal (call this
). Use the Pythagorean Theorem again with the triangle formed by
,
, and
to find the length of this diagonal.
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Find the length of the diagonal of the following cube:

Find the length of the diagonal of the following cube:

To find the length of the diagonal, use the formula for a
triangle:


The length of the diagonal is
.
To find the length of the diagonal, use the formula for a triangle:
The length of the diagonal is .
Compare your answer with the correct one above
What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
What is the length of the diagonal of a cube with a side length of
? Round to the nearest hundreth.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
It is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
What is the length of the diagonal of a cube with a volume of
? Round to the nearest hundredth.
What is the length of the diagonal of a cube with a volume of
? Round to the nearest hundredth.
First, you need to find the side length of this cube. We know that the volume is:
, where
is the side length.
Therefore, based on our data, we can say:

Solving for
by taking the cube-root of both sides, we get:

Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:
(Note that not all points are drawn in on the cube.)

The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
First, you need to find the side length of this cube. We know that the volume is:
, where
is the side length.
Therefore, based on our data, we can say:
Solving for by taking the cube-root of both sides, we get:
Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:
(Note that not all points are drawn in on the cube.)

The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
What is the length of the diagonal of a cube with a surface area of
? Round your answer to the nearest hundredth.
What is the length of the diagonal of a cube with a surface area of
? Round your answer to the nearest hundredth.
First, you need to find the side length of this cube. We know that the surface area is defined by:
, where
is the side length. (This is because the cube is
sides of equal area).
Therefore, based on our data, we can say:


Take the square root of both sides and get:

Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and 
Solve this by using the distance formula. This is very easy since one point is all
s. It is merely:

This is approximately
.
First, you need to find the side length of this cube. We know that the surface area is defined by:
, where
is the side length. (This is because the cube is
sides of equal area).
Therefore, based on our data, we can say:
Take the square root of both sides and get:
Now, it is easiest to think about diagonals like this by considering two points on a cube (if it were drawn in three dimensions). We could draw it like this:

(Note that not all points are drawn in on the cube.)
The two points we are looking at are:
and
Solve this by using the distance formula. This is very easy since one point is all s. It is merely:
This is approximately .
Compare your answer with the correct one above
Suppose the volume of a cube is
. What is the length of the diagonal?
Suppose the volume of a cube is . What is the length of the diagonal?
Write the equation for the volume of a cube. Substitute the volume to find the side length,
.



Write the equation for finding diagonals given an edge length for a cube.

Substitute the side length to find the diagonal length.
The answer is
.
Write the equation for the volume of a cube. Substitute the volume to find the side length, .
Write the equation for finding diagonals given an edge length for a cube.
Substitute the side length to find the diagonal length.
The answer is .
Compare your answer with the correct one above
Find the diagonal of a cube with a side length of
.
Find the diagonal of a cube with a side length of .
The diagonal of a cube is simply given by:

Where
is the side length of the cube.
So since our 


The diagonal of a cube is simply given by:
Where is the side length of the cube.
So since our
Compare your answer with the correct one above