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SAT math essentials part 7

Tham khảo tài liệu 'sat math essentials part 7', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | GEOMETRY REVIEW What is the length of c in the triangle above a. 30 b. 40 c. 60 d. 80 e. 100 Answer d. You could use the Pythagorean theorem to solve this question but if you notice that the triangle shows two parts of a Pythagorean triple you don t have to. 60 c 100 is a multiple of 6 8 10 which is a multiple of 3 4 5 . Therefore c must equal 80 because 60 80 100 is the same ratio as 6 8 10. 45-45-90 Right Triangles An isosceles right triangle is a right triangle with two angles each measuring 45 . Special rules apply to isosceles right triangles the length of the hypotenuse Vi X the length of a leg of the triangle 115 GEOMETRY REVIEW V2 the length of each leg is 2 x the length of the hypotenuse 2 You can use these special rules to solve problems involving isosceles right triangles. Example In the isosceles right triangle below what is the length of a leg x x X the length of the hypotenuse V2 . . x -yr X 28 28V2 x 2 x 14V2 116 GEOMETRY REVIEW What is the length of a in the triangle above 15V2 a. I b. 1S4 c. 15 V2 d. 30 e. 30V2 Answer c. In an isosceles right triangle the length of the hypotenuse V2 X the length of a leg of the triangle. According to the figure one leg 15. Therefore the hypotenuse is 15 V2. 30-60-90 Triangles Special rules apply to right triangles with one angle measuring 30 and another angle measuring 60 . the hypotenuse 2 X the length of the leg opposite the 30 angle the leg opposite the 30 angle 2 X the length of the hypotenuse the leg opposite the 60 angle V3 X the length of the other leg You can use these rules to solve problems involving 30-60-90 triangles. .