The perimeter of rectangle ABCD is 96 cm

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?

  1. 6
  2. 18
  3. 30
  4. 36
  5. 60

Answer

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

Now,

AB = 3k = 3(6) = 18 cm