stim ca unghiurile opuse sunt congruente si masura unghiurilor unui paralelogram=360 grade
deci ung.A≡ungh.C⇒C=38 grade
A,B,C,D,-MASURILE UNGIURILOR A,B,C,D
A+B+C+D=360 GRADE
38+B+38+D=360 GRADE
B+D=360-38-38
B+D=284 GRADE
CUM B≡D⇒B=284/2=142
B=142 GRADE
D=142 GRADE
DECI
38+142+38+142=360 GRADE