Question 580433
"the ratio of the length to the width is 7:5" means that the length is 7x and the width is 5x for some unknown value of x. 



So L = 7x and W = 5x. Also, we know that the perimeter is 96 cm, so P = 96. 



Now use the perimeter formula to solve for x



P = 2L + 2W


96 = 2(7x) + 2(5x)


96 = 14x + 10x


96 = 24x


96/24 = 24x/24


4 = x


x = 4



So the value of x is x = 4. This means that the length is 7x = 7*4 = 28 and the width is 5x = 5*4 = 20



So in short, the length is 28 cm and the width is 20 cm