Question

What is length of Ef?
A.10
B.15
C.20
D.v200
E.v300
F.v500

Answer 1

Answer E is correct

Explanation:

Let the Length of EF be x

Use PYTHAGORAS theorem to find the length of EF

EF² + DF² = DE²

`{x}^(2) + {10}^(2) = {20}^(2) \\ {x}^(2) + 100 = 400 \\ {x}^(2) = 400 - 100 \\ {x}^(2) = 300 \\ x = √(300)`

So,

`EF = √(300)`

Hope this helps you.

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