Question

Given: ABCD is a trapezoid, AB = CD, BK ⊥ AD, AK = 10, KD = 20
Find: BC AD

Answer 1

AK=10; KD=20
AD=AK+KD
AD=10+20
AD=30

Like AB=CD this trapezoid is symmetric, then if we draw CL ⊥ AD:
LD=AK→LD=10
BC=KL=KD-LD=20-10→BC=10

Answers:
BC=10
AD=30