如图,在Rt△ABC中,∠C=90°,AD平分∠CAB,交BC于点D,CD=2,AC=2.(1)求∠B的度数;(2)求AB和BC的长. 答案:【答案】(1)30°;(2). 【解析】(1)根据∠C=90°,CD=2,AC=得出∠CAD=30°,AD平分∠CAB,即可求出∠B.(2)由(1)中∠B=30°,利用勾股定理即可求出BC.解:(1)∵在Rt△ACD中,∠C=90°,CD=2,AC=,∴tan∠CAD===,∴∠CAD=30°,∵AD平分∠CAB,∴∠CAB=2∠CAD=60°,∵∠C=90°,∴∠B=90°The boy said ________ couldn’t he work out
the problem but his teacher didn’t know how to do it.
A.though
B.never
C.hardly
D.not only