McGraw-Hill Education GRE 2019

A

12

5

B C

What is the perimeter of the triangle above?

A 13

B 17

C 25

D 30

E 42

SOLUTION: To determine the perimeter, solve for side BC, which is the

hypotenuse. You can use the Pythagorean theorem to solve for the

hypotenuse:

52 + 12^2 = c^2

169 = c^2

13 = c

Thus the perimeter is 5 + 12 + 13 = 30.

Pythagorean Triplets

There are certain combinations of right-triangle side lengths that occur throughout

the GRE. Though you can always use the Pythagorean theorem in these situations,

you will save precious time by memorizing these triplets and their multiples:

A

4

3 5

B C

COMBINATIONS TRIPLETS

3-4-5 6 - 8 -10

32 + 4^2 = 5^2 9 -12-15

9 + 16 = 25 12-16 -20

A

12

5

13

B C

COMBINATIONS TRIPLETS

5 -12-13 10 -24 -26

52 + 12^2 = 13^2

25 + 144 = 169

15

8 17

COMBINATIONS TRIPLETS

8 -15 -17 None

82 + 15^2 = 17^2

64 + 225 = 289

CHAPTER 13 ■ GEOMETRY 381

04-GRE-Test-2018_313-462.indd 381 12/05/17 12:04 pm