Question

1. The perimeter of a rectangle is 78 cm. The length is 3 greater than twice its width. Find the dimensions.

Answer 1

P=2(L+W)
P=78
L=3+2W

78=2(L+W)
divide both sides by 2
39=L+W
sub 3+2W for L
39=3+2W+W
39=3+3W
minus 3 both sides
36=3W
divide both sides by 3
12=W
width=12
sub back to find length

L=3+2W
L=3+2(12)
L=3+24
L=27


it is 12 by 27