Question

I don’t understand this

Answer 1

DE = 8

Explanation:

Since the 3 angles are congruent then the triangle is equilateral with 3 congruent sides , then

5x - 12 = 3x - 4 ( subtract 3x from both sides )

2x - 12 = - 4 ( add 12 to both sides )

2x = 8 ( divide both sides by 2 )

x = 4

Then

EF = 3x - 4 = 3(4) - 4 = 12 - 4 = 8 , so

DE = EF = 8