Answer:
angle edf is 70
Step-by-step explanation:
triangle angles always add up to 180. So if you have 40 degrees at angle e already, 180-40 = 140
since side DE and side EF are congruent, that means its an isosceles triangle. One rule for that type a triangle is that the two base angles are equal. So you can just do 140/2 = 70
hope that helps!
