Question

What is length of Ef?

Answer 1

Choice e) radical 300

Answer 2

Step-by-step explanation:

Using Pythagoras ;

$20=\sqrt{10^{2}+x^{2} } \\20^{2}=10^{2}+ x^{2}\\400 = 100 +x^{2} \\300 = x^{2} \\x =\sqrt{300}$

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