BC⊥AD,BC⊥PO, so BC⊥ Police station.

So AP⊥BC

When bm⊥ap BM∩BC = b, then AP⊥ BMC.

At this time, dihedral angle A-MC-B is a straight dihedral angle.

ab^2=ad^2+bd^2=25+ 16=4 1

AB= Geng Hao 4 1

AP^2=AO^2+PO^2=25

AP=5

Connect BO, bo 2 = BD 2+do 2 = 16+4 = 20.

PB^2=PO^2=BO^2=20+ 16=36

PB=6

Let AM=X

AB^2-AM^2=PB^2-PM^2

4 1-X^2=36-(5-X)^2

X=3

So AM=3