Question 903914
The perimeter of the rectangle is the wire, which is 42cm.
P = 2length + 2width
You're given the width as twice its length.
P = 2L + 2W
P = 42
W = 2L
Substitute the value of W from the bottom equation into the top
P = 2L + 2W
P = 2L + 2(2L)
Distribute
42 = 2L + 4L
42 = 6L
Divide each side by 6
7 = L
If the length is 7, then the width is twice that, or 14
7 + 7 + 14 + 14 = 42