Respostas

2013-09-24T21:52:29-03:00
Área
x/y = 3/7
7x = 3y
x = 3y/7

Perímetro
2x + 2y = 120
2.(3y/7) + 2y = 120
6y/7+ 2y= 120
6y + 14y = 840
20y = 840
y = 840/20
y = 42 cm

x = 3y/7
x = 3.42/7
x = 126/7
x = 18 cm

A = 42*18
A = 756 cm²

Resposta: 756 cm²