7) bce = 120 + (180-120)/2 = 150
8) coq = pot/2 + (180-pot)/2=180/2=90
9) tln = 180 - klr/2=180-40/2=160
10) doe=(180 - cob)/2 + cob-30 = (180 - 90)/2 + 90-30 = 45+60=105
11) mcp+psn=180
msp+psn+90=180+90
msp+msp=270
msp=135
12) amn = 1/2 (amc+dmb) + 1/2(cmd) = 1/2*(amc+dmb+cmd)=1/2*180=90