Basic Geometry : Quadrilaterals

Study concepts, example questions & explanations for Basic Geometry

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Example Questions

Example Question #762 : Plane Geometry

Find the area of a square if it has a diagonal of \(\displaystyle \sqrt{34}\).

Possible Answers:

\(\displaystyle 17\sqrt3\)

\(\displaystyle 17\)

\(\displaystyle 17\sqrt2\)

\(\displaystyle \frac{17\sqrt2}{2}\)

Correct answer:

\(\displaystyle 17\)

Explanation:

The diagonal of a square is also the hypotenuse of a \(\displaystyle 45-45-90\) triangle.

Picture1

Recall how to find the area of a square:

\(\displaystyle \text{Area}=\text{side}^2\)

Now, use the Pythagorean theorem to find the area of the square.

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

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

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

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Substitute in the length of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{(\sqrt{34})^2}{2}\)

Simplify.

\(\displaystyle \text{Area}=\frac{34}{2}\)

\(\displaystyle \text{Area}=17\)

Example Question #763 : Plane Geometry

Find the area of a square if it has a diagonal of \(\displaystyle 12\sqrt3\).

Possible Answers:

\(\displaystyle 108\sqrt2\)

\(\displaystyle 216\sqrt3\)

\(\displaystyle 216\)

\(\displaystyle 432\sqrt2\)

Correct answer:

\(\displaystyle 216\)

Explanation:

The diagonal of a square is also the hypotenuse of a \(\displaystyle 45-45-90\) triangle.

Picture1

Recall how to find the area of a square:

\(\displaystyle \text{Area}=\text{side}^2\)

Now, use the Pythagorean theorem to find the area of the square.

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

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

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

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Substitute in the length of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{(12\sqrt3)^2}{2}\)

Simplify.

\(\displaystyle \text{Area}=\frac{432}{2}\)

\(\displaystyle \text{Area}=216\)

Example Question #361 : Quadrilaterals

Find the area of the square.

2

Possible Answers:

\(\displaystyle 1764\)

\(\displaystyle 84\sqrt2\)

\(\displaystyle 882\)

\(\displaystyle 1264\sqrt3\)

Correct answer:

\(\displaystyle 882\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{42^2}{2}\)

Solve.

\(\displaystyle \text{Area}=882\)

Example Question #81 : How To Find The Area Of A Square

Find the area of the square.

3

Possible Answers:

\(\displaystyle 968\)

\(\displaystyle 224\sqrt3\)

\(\displaystyle 1936\)

\(\displaystyle 968\sqrt2\)

Correct answer:

\(\displaystyle 968\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{44^2}{2}\)

Solve.

\(\displaystyle \text{Area}=968\)

Example Question #361 : Quadrilaterals

Find the area of the square.

3

Possible Answers:

\(\displaystyle 224\sqrt3\)

\(\displaystyle 968\)

\(\displaystyle 1936\)

\(\displaystyle 968\sqrt2\)

Correct answer:

\(\displaystyle 968\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{44^2}{2}\)

Solve.

\(\displaystyle \text{Area}=968\)

Example Question #772 : Plane Geometry

Find the area of the square.

5

Possible Answers:

\(\displaystyle 1152\sqrt2\)

\(\displaystyle 576\sqrt3\)

\(\displaystyle 1152\)

\(\displaystyle 2304\)

Correct answer:

\(\displaystyle 1152\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{48^2}{2}\)

Solve.

\(\displaystyle \text{Area}=1152\)

Example Question #81 : How To Find The Area Of A Square

Find the area of the square.

6

Possible Answers:

\(\displaystyle 1250\)

\(\displaystyle 1250\sqrt3\)

\(\displaystyle 2500\sqrt2\)

\(\displaystyle 625\sqrt3\)

Correct answer:

\(\displaystyle 1250\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{50^2}{2}\)

Solve.

\(\displaystyle \text{Area}=1250\)

Example Question #91 : How To Find The Area Of A Square

Find the area of the square.

7

Possible Answers:

\(\displaystyle 1352\)

\(\displaystyle 676\sqrt3\)

\(\displaystyle 338\)

\(\displaystyle 2704\)

Correct answer:

\(\displaystyle 1352\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{52^2}{2}\)

Solve.

\(\displaystyle \text{Area}=1352\)

Example Question #772 : Basic Geometry

Find the area of the square.

8

Possible Answers:

\(\displaystyle 1458\)

\(\displaystyle 729\)

\(\displaystyle 2916\)

\(\displaystyle 365\sqrt2\)

Correct answer:

\(\displaystyle 1458\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{54^2}{2}\)

Solve.

\(\displaystyle \text{Area}=1458\)

Example Question #91 : How To Find The Area Of A Square

Find the area of the square.

9

Possible Answers:

\(\displaystyle 3136\)

\(\displaystyle 1998\)

\(\displaystyle 2428\)

\(\displaystyle 1568\)

Correct answer:

\(\displaystyle 1568\)

Explanation:

The diagonal of a square is also the hypotenuse of a right isosceles triangle that has the sides of the square as its legs.

Thus, we can use the Pythagorean Theorem to find the length of the sides of the square.

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

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

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

Recall how to find the area of a square.

\(\displaystyle \text{Area}=\text{side}^2=\frac{\text{Diagonal}^2}{2}\)

Now, substitute in the value of the diagonal to find the area of the square.

\(\displaystyle \text{Area}=\frac{56^2}{2}\)

Solve.

\(\displaystyle \text{Area}=1568\)

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