d(M,AB)=MA=12
=>d(M,AD)=MA=12
=>MB²=MA²+AB²=12²+16²=144+256=400 => MB=20
=>d(M,BC)=MB=20
=>MD²=MA²+AD²=12²+16²=144+256=400 => MD=20
=>d(M,CD)=MD=20
=> ca MD=MB pt ca ΔMAD≡ΔMAB
AC=AD√2=16√2
fie AC intersectat cu BD={O}
AO=AC/2=16√2/2=8√2
MO²=OA²+MA²=8²*2+12²=128+144=272=4√17
d(M, BD)=MO=4√17