A/2 =B/4 = C/6 = D/8 = K (A/2 inseamna A : 2 adica linie de fractie)
A/2 = K → A = 2k
B = 4 k
C = 6 K
D = 8 k
Suma masurilor unghiurilor unui patrulater e de 360°
A + B +C+ D = 360
2k + 4 k + 6 k + 8 k = 360
20 k = 360
K = 360 :20
K = 18
A = 2 k
A = 18 x 2
A = 36
B= 4 k
B = 72
C= 6 k
C = 108
D= 8k
D = 144