the permiter of a rectangle is 84cm. The length is twice the width. Find the length and the width

Question

i cant understand how to do this problem

Answer 1

Here's what we know:

P_rec = 2L + 2w (Rectangular perimeter equals the 2 lengths and widths added together)

P = 84

L = 2w (the length is twice as long as the width)

 

If we put the pieces together, we get:

84 = 2(2w) + 2w

Simplifying, that leaves us with:

84 = 6w

 

You should be able to find the width--and use that to find the length--from here.