The perimeter of rectangle ABCD is 96 cm. The ratio of the side lengths AB:BC is 3:5. What is the length, in centimeters, of AB?
The correct answer is B.
You can use the formula for the perimeter of a rectangle.
P = 2(w + l) with P = 96, AB = w, and BC = l
96 = 2(AB + BC)
AB + BC = 48
Using this equation and the given ratio with k as the constant of proportionality, we have AB = 3k and BC = 5k.
So, the equation becomes
3k + 5k = 48
8k = 48
k = 6
AB = 3k = 3(6) = 18 cm