Basic Geometry : Quadrilaterals

Study concepts, example questions & explanations for Basic Geometry

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Example Questions

Example Question #261 : Quadrilaterals

Find the length of the diagonal of a square with side lengths of \(\displaystyle 22\).

Possible Answers:

\(\displaystyle 11\sqrt2\)

\(\displaystyle 16\sqrt2\)

\(\displaystyle 22\sqrt2\)

\(\displaystyle 15\sqrt2\)

Correct answer:

\(\displaystyle 22\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=22\sqrt2\)

Example Question #262 : Quadrilaterals

Find the length of the diagonal of a square with a side length of \(\displaystyle 12\).

Possible Answers:

\(\displaystyle 12\)

\(\displaystyle 6\sqrt2\)

\(\displaystyle 16\sqrt2\)

\(\displaystyle 12\sqrt2\)

Correct answer:

\(\displaystyle 12\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=12\sqrt2\)

Example Question #261 : Quadrilaterals

Find the length of the diagonal of a square that has a side length of \(\displaystyle 5\).

Possible Answers:

\(\displaystyle 2.5\)

\(\displaystyle 5\sqrt2\)

\(\displaystyle 5\)

\(\displaystyle 10\sqrt2\)

Correct answer:

\(\displaystyle 5\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=5\sqrt2\)

Example Question #11 : How To Find The Length Of The Diagonal Of A Square

Find the length of the diagonal of a square that has a side length of \(\displaystyle 159\).

Possible Answers:

\(\displaystyle 159\)

The length of the diagonal cannot be determined.

\(\displaystyle 159\sqrt2\)

\(\displaystyle 169\sqrt2\)

Correct answer:

\(\displaystyle 159\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=159\sqrt2\)

Example Question #262 : Quadrilaterals

Find the length of the diagonal of a square with side lengths of \(\displaystyle 27\).

Possible Answers:

\(\displaystyle 25\sqrt2\)

\(\displaystyle 9\sqrt2\)

\(\displaystyle 28\sqrt2\)

\(\displaystyle 27\sqrt2\)

Correct answer:

\(\displaystyle 27\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=27\sqrt2\)

Example Question #15 : Squares

Find the length of the diagonal of a square that has a side length of \(\displaystyle 23\).

Possible Answers:

\(\displaystyle 46\sqrt2\)

\(\displaystyle 54\sqrt2\)

\(\displaystyle 23\)

\(\displaystyle 23\sqrt2\)

Correct answer:

\(\displaystyle 23\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=23\sqrt2\)

Example Question #16 : Squares

Find the length of the diagonal of a square with side lengths of \(\displaystyle 122\).

Possible Answers:

\(\displaystyle 122\sqrt2\)

\(\displaystyle 244\sqrt2\)

\(\displaystyle 61\sqrt2\)

\(\displaystyle 122\)

Correct answer:

\(\displaystyle 122\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=122\sqrt2\)

Example Question #17 : Squares

Find the length of the diagonal of a square that has side lengths of \(\displaystyle 35\).

Possible Answers:

\(\displaystyle 17\sqrt2\)

\(\displaystyle 35\)

\(\displaystyle 70\sqrt2\)

\(\displaystyle 35\sqrt2\)

Correct answer:

\(\displaystyle 35\sqrt2\)

Explanation:

The diagonal of a square is also a hypotenuse of a right triangle with the side lengths as legs of the triangle.

1

Use the Pythagorean Theorem to find the length of the diagonal.

\(\displaystyle \text{Diagonal}=\sqrt{\text{side length}^2+\text{side length}^2}\)

\(\displaystyle \text{Diagonal}=\sqrt{2(\text{side length})^2}\)

\(\displaystyle \text{Diagonal}=(\text{side length})\sqrt2\)

For the square given in the question,

\(\displaystyle \text{Diagonal}=35\sqrt2\)

Example Question #262 : Quadrilaterals

Find the length of the diagonal of a square whose side length is \(\displaystyle 8\).

Possible Answers:

\(\displaystyle 8\sqrt{2}\)

\(\displaystyle 16\sqrt{2}\)

\(\displaystyle 16\)

\(\displaystyle 64\)

Correct answer:

\(\displaystyle 8\sqrt{2}\)

Explanation:

To find the diagonal, you case use the pythagorean theorem or realize that this in isosceles triangle, and therefore the hypotenuse is

\(\displaystyle s\sqrt{2}=8\sqrt{2}\)

Example Question #21 : How To Find The Length Of The Diagonal Of A Square

A square has side lengths of \(\displaystyle 15ft\). Find the length of the diagonal. 

Possible Answers:

\(\displaystyle 27.4ft\)

\(\displaystyle 21.2ft\)

\(\displaystyle 20ft\)

\(\displaystyle 23.2ft\)

\(\displaystyle 24.5ft\)

Correct answer:

\(\displaystyle 21.2ft\)

Explanation:

Finding the diagonal of a square is the same as finding the hypotenuse of a triangle, and uses the Pythagorean Theorem. (Imagine the square being sliced diagonally into two triangles, for you visual learners.) Within this theorem, both a and b are the same number, since the sides of a square are equal. 

\(\displaystyle a^2 + b^2 = c^2\)

\(\displaystyle 15^2 + 15^2 = c^2\)

\(\displaystyle 225 + 225 = c^2\)

\(\displaystyle 450 = c^2\)

\(\displaystyle \sqrt{}450 = c\)

\(\displaystyle 21.2 ft = c\)

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