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