Fundamentals of Math

Fundamentals of Mathematics

5.2 Pythagorean Theorem

Credited to the mathematician Pythagoras in approximately 500 BCE, the Pythagorean Theorem states that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides. The side opposite to the right angle of the right triangle is known as the hypotenuse, and the sides that form the right angle are known as the legs.

Leg 1 is often denoted , leg 2 as , and the hypotenuse as . Note: It does

not matter which leg you call or which leg you call .

Knowing this theorem, you can find the measurement of any side length of a right triangle as long as at least two of the sides are known.

Example 5.2

2 + 2 = 2

⇒ (4) 2 + (3) 2 = 2

⇒ 16 + 9 = 2

⇒ 25 = 2

⇒ √25 = √ 2

⇒ = 5

Practice 5.2

Directions: Determine the missing length in each right triangle using the Pythagorean theorem.

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Answer Key on Page 122

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