如图,△ACB≌△A′CB′,∠BCB′=30°,则∠ACA′的度数为(  ) A.20° B.30° C.35° D.40°

问题描述:

如图,△ACB≌△A′CB′,∠BCB′=30°,则∠ACA′的度数为(  )
A. 20°
B. 30°
C. 35°
D. 40°

∵△ACB≌△A′CB′,
∴∠ACB=∠A′CB′,
即∠ACA′+∠A′CB=∠B′CB+∠A′CB,
∴∠ACA′=∠B′CB,
又∠B′CB=30°
∴∠ACA′=30°.
故选:B.