Question

The formula for finding the perimeter of a rectangle with length, l, and width, w, is P = 2l + 2w.

If the length and width of a rectangle are both doubled, how is the perimeter affected?


A. The perimeter remains the same.
B. The perimeter is multiplied by 1/2
C. The perimeter is twice as great.
D. The perimeter is four times as great.

Answer 1

The perimeter will grow by a factor of 2, so C is the correct answer.

Answer 2

p1=2(l+w)---->(equation 1)
after the length and the width are doubled
p2=2(2l+2w)
we will take 2 common factor out of the bracket
p2=2(2(l+w))
then from equation1
p2=2p1
then the answer is the choice number c