Question

P是距形ABCD所在平面外一点,且PA垂直于平面ABCD.则以P.A.B.C.D五点中的三点为顶点的直角三角形个数为?

Answer 1

底面：Rt△ABC、Rt△BCD、Rt△CDA、Rt△ABD

侧面：Rt△PAB、Rt△PAD、Rt△PBC、Rt△PDC

对角面：Rt△PAC