A 42 inch wire is bent into the shape of a rectangle whose width is twice its length. Set up an equation to find the length of the rectangle.

Choice A

2(2L + L)  = 42

Explanation:

The length is L, which is some placeholder for a positive number.

The width is twice as much as this, so it's 2L

The perimeter is found by adding up the four sides (two of which are L, the other two are 2L)

So we have L+L+2L+2L = 2(2L+L) representing the perimeter.

Or we could use this formula

P = 2(L+W)

where L and W are the length and width respectively.

Either way, we end up with 2(2L + L) = 42

42 = 2( l+2l)

Step-by-step explanation:

width = 2 length

Perimeter = 2 (l+w)

42 = 2( l+2l)

Divide each side by 2

42/2 = 2 (3l) /2

21 = 3l

Divide by 3

21/3 = 3l/3

7 = l

The length is 7

width is 2*l = 2*7 = 14