Grade 7 Algrebra

Question

The width of a rectangle 4 cm longer than two-thirds of its length. What is the area if the perimeter is 78 cm?

Answer 1

W = 4 + 2L/3

2L + 2W = 78

2L + 2(4+2L/3) = 78

L + 4 + 2L/3 = 78/2 = 39

5L/3 = 39-4 = 35

L = (3/5)35 = 21 cm long

W = 4+(2/3)21 = 4 +14 = 18 cm wide

Area = LW = 21(18) = 378 cm^2