PM=PN

& ltN = & ltM

& ltP = & ltP

So the triangle PNA is equal to the triangle PBM.

So PB=PA

So AM=PM-PA=PN-PB=BN

Connecting DC

In RT triangular ADC and RT triangular BCD.

AD = BC

DC=DC

So RT triangular ADC is equal to RT triangular BCD.

So AC=BD