Reprezentăm grafic:
/___a/2_____//___a/2_____/
a
/___a/2_____//___a/2_____//___a/2_____/ = 3
c
/__b/3__//__b/3___//__b/3___/
b
/__b/3__//__b/3___//__b/3___//__b/3__//__b/3___//__b/3___/ = 6;
c
Facem calculele:
c : a/2 = 3; 2c/a = 3; 2c = 3a; c = 3a/2;
c : b/3 = 6; 3c/b = 6; 3c = 6b; c = 2b
c - b = 90; 2b - b = 90;
b = 90;
c = 2x90 = 180;
c = 180;
a = 2c/3 = 2x180/3 = 2x60 = 120;
a = 120.