Question

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

E
13
Å
D 7 F
A. 120
B. 1920
ООО
C. 218
D. 1218

Answer 1

B

Explanation:

Using Pythagoras' identity in the right triangle.

The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is

EF² + DF² = DE² , that is

EF² + 7² = 13²

EF² + 49 = 169 ( subtract 49 from both sides )

EF² = 120 ( take the square root of both sides )

EF =
`√(120)` → B