High School Math : How to find the length of the hypotenuse of a 45/45/90 right isosceles triangle : Pythagorean Theorem

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 :45/45/90 Right Isosceles Triangles

Isosceles

In an isosceles right triangle, two sides equal. Find the length of side.

Possible Answers:

Correct answer:

解释:

This problem represents the definition of the side lengths of an isosceles right triangle. By definition the sides equal,, and. However, if you did not remember this definition one can also find the length of the side using the Pythagorean theorem.

Example Question #1 :45/45/90 Right Isosceles Triangles

ABCDis a square whose side isunits. Find the length of diagonalAC.

Possible Answers:

none of the other answers

Correct answer:

解释:

To find the length of the diagonal, given two sides of the square, we can create two equal triangles from the square. The diagonal line splits the right angles of the square in half, creating two triangles with the angles of,, anddegrees. This type of triangle is a special right triangle, with the relationship between the side opposite thedegree angles serving as x, and the side opposite thedegree angle serving as.

Appyling this, if we plugin forwe get that the side opposite the right angle (aka the diagonal) is

Example Question #3 :45/45/90 Right Isosceles Triangles

The area of a square is. Find the length of the diagonal of the square.

Possible Answers:

Correct answer:

解释:

If the area of the square is, we know that each side of the square is, because the area of a square is.

Then, the diagonal creates twospecial right triangles. Knowing that the sides =, we can find that the hypotenuse (aka diagonal) is

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