a)Masurile unghiurilor unui patrulater=360
Unghiurile opuse ale paralelogramului sunt congruente.
A+B+C+D=360
A/2=B/4=C/2=D/4=k
A=2k
B=4k
C=2k
D=4k
2k+4k+2k+4k=360
12k=360 =>k=30
=>A=60
B=120
C=60
D=120
b)La fel procedam
2,(3)=2 intregi 3/9=21/9=7/3
1,(6)=1 intreg 6/9=15/9=5/3
7A/3=5B/3=7C/3=5D/3=k
A=3k/7
B=3k/5
C=3k/7
D=3k/5
3k/7 + 3k/5 + 3k/7 + 3k/5=360
Numitorul comun este 35
15k+21k+15k+21k=12600
72k=12600 =>k=175
=>A=75
B=105
C=75
D=105