如果一个角的补角是这个角的4倍,那么这个角为多少度?
设这个角为x,则它的补角为180°-x,
由题意得,180°-x=4x,
解得:x=36°.
答:这个角为36°.
交流调压调速的制动方式有()制动.
A.反接
B.涡流
C.能耗
D.机械
What are they doing? They are .[ ]
A. play
B. plays
C. playing