latura patrat = a, perimetrul = 4 × a
lungime dreptunghi = 64 m
latime dreptunghi = 2a/3 deci Perimetrul dreptunghi=2×(64+2a/3)
4 × a = 3/5(2×64 + 2× 2a/3)
4 × a = 3/5(128 + 4a/3)
4 × a = 384/5 + 12a/15
60a = 1152 + 12a⇒ 48a = 1152
a = 24 m latura patrat
latime dreptunghi= 2/3 din a =(2/3)×24 = 2 ×24/3 = 16 cm
lungime dreptunghi = 64 cm iar latime = 16 cm
P dreptunghi = 2× (64+16) = 160 cm