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Pythagorean Theorem. a² + b² = c². Click here to see the animation. Pythagorean Theorem. a² + b² = c². c is ALWAYS the “hypotenuse” the LONGEST side across from the right angle. c² - b² = a². a or b is a “leg”. c² - a² = b². a or b is a “leg”. Find the missing length. 5. 3. 4.
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Pythagorean Theorem a² + b² = c² Click here to see the animation
Pythagorean Theorem a² + b² = c² c is ALWAYS the “hypotenuse” the LONGEST side across from the right angle c² - b² = a² a or b is a “leg” c² - a² = b² a or b is a “leg”
Find the missing length 5 3 4
Find the missing length 10 6 8
Find the missing length 15 9 12
Find the missing length 25 15 20
Those were nice “3, 4, 5” trianglesHere is information on “triples”
Find the unknown length for the triangle shown. This is neither a triple, or a 3,4,5. SOLUTION b2 c2 a2 + Pythagorean theorem = a2 + 62 = 72 Substitute 6 for band 7 for c. a2 + 36 = 49 Simplify. a Take positive square root of each side. = 13 The side length ais ANSWER 13. Example 1 Use the Pythagorean theorem a2 = 13 Subtract 36 from each side.
Guided Practice for Example 1 5² + 12² = c² ANSWER 25 + 144 = c² 169 = c² √169 = √c² 13 = c The lengths of the legs of a right triangle areand 1. a = 5 b = 12. Find c.
Multiple Choice Practice Example 2 In the triangle shown, D is the midpoint of segment AC, and segment BD is perpendicular to segment AC. What is the length of segment BD? 12 cm 14 cm 23 cm 16 cm
c2 a2 + b2 Pythagorean theorem = SOLUTION The path of the kicked ball is the hypotenuse of a right triangle. The length of one leg is 12 yards, and the length of the other leg is 40 yards. Example 3 Solve a real-world problem SOCCER A soccer player makes a corner kick to another player, as shown. Find the distance the player kicks the ball.
Example 3 Solve a real-world problem c2 122 + 402 Substitute 12 for aand 40 for b. = c2 1744 Simplify. = Take positive square root of each side. c2 = 42 ≈ 1744 The player kicks the ball about 42 yards. ANSWER
The Pythagorean Theorem can be used to check and see if the lengths will form a right triangle when connected
Example 4 Determine right triangles Tell whether the triangle with the given side lengths is a right triangle. a. 8, 15, 17 ? 82 + 152 172 = ? 289 64 + 225 = 289 289 = The triangle is a right triangle. ANSWER
The triangle is not a right triangle. ANSWER Example 4 Determine right triangles Tell whether the triangle with the given side lengths is a right triangle. b. 5, 8, 9 ? 52 + 82 92 = ? 25 + 64 81 = 89 81 =
Guided Practice for Examples 4 and 5 Tell whether the triangle with the given side lengths is a right triangle. not a right triangle 4. 7, 11, 13 ANSWER 5. 15, 36, 39 right triangle ANSWER right triangle ANSWER 6. 15, 112, 113