Question

What is the length of EF in the right triangle below?

Answer 1

Use the Pythagorean theorem:

`|DF|^2+|EF|^2=|DE|^2`

We have |DF| = 12 and |DE| = 19. Substitute:

`12^2+|EF|^2=19^2\\\\144+|EF|^2=361\qquad|-144\\\\|EF|^2=217\to|EF|=√(217)`

Answer:
`C.\ √(217)`