La 12 punctul a)
ABC +CBD =180
AMB=ABC/2
CBD=AMB/2=(ABC/2)/2=ABC/4 ceea ce inseamna ca ABC=CBD*4
CBD*4+CBD=180
CBD=180/5
=36
ABM=CBD*2=72
ABC=ABM*2=144
DBM=CBD+MBC(MBC=ABM)=108
