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

Answer: BC = 10 and AD = 30Step-by-step explanation:In figure-1 , AB = CD ,BK ⊥ AD,  AK = 10,  KD = 20.Since, line AD is sum of AK and  KD, thenAD = AK + KDAD = 10 + 20AD = 30Since, BC ║AD and BK ⊥ AD then similarly we construct CL ⊥ AD so, BC = KL and AK = LDKL = AD - LDKL = 20 - 10KL = 10Since, BC = KL then BC = 10Hence, BC = 10 and AD = 30