Question

In the right triangle shown, DF=EF=3. How long is DE

Answer 1

Answer:

$DE=3\sqrt{2}\ units$

Step-by-step explanation:

see the attached figure to better understand the problem

In this problem we have an isosceles right triangle (because has two equal sides)

so

Applying the Pythagorean theorem

$DE^2=DF^2+EF^2$

substitute the given values

$DE^2=3^2+3^2$

$DE^2=18\\DE=3\sqrt{2}\ units$