Question

The perimeter of a rectangle is 42 cm. One side is 9 cm longer than the other side. Find the lengths of the sides.

Answer 1

P=2(L+W)
P=42
42=2(L+W)
21=L+W



one side is 9 longer than other
L=9+W
subsitute

21=L+W
21=9+W+W
21=9+2W
minus 9 both sides
12=2W
divide by 2 both sides
6=W

sub back

L=9+W
L=9+6
L=15


the sides are lenght 15cm and 6cm