Answer:
Width=9 cm; Length= 12 cm
Step-by-step explanation:
Perimeter=2 times (Length)+ 2 times (Width)
Then you would substitute the lengths in, which would get you,
42=2(L) + 2(W)
Since the length is greater than the width by 3, L=W+3
Substitute this in, then you get,
42=2(W+3)+ 2(W) Solve,
42=2W+6+2W
42=4W+6
36=4W
W=9 cm
L=W+3
L=9+3
L=12 cm
