The length of a rectangle is 2 times it’s width if the perimeter of the rectangle is 36 inches find it’s length and width

P = Perimeter            

L = Length          

W = Width

Perimeter of rectangle = L + L + W + W        

or P = 2L + 2W

You know:

P = 36 inches

L = 2W          [length is(=) 2 times it's width]

W = ?

P = 2L + 2W    

Substitute/plug in what you know, plug in 2W for L since L = 2W

36 = 2(2W) + 2W         Simplify

36 = 4W + 2W

36 = 6W        Divide 6 on both sides

6 = W              Now that you know the width, you can find the length:

L = 2W

L = 2(6)

L = 12

L = 12 in

W = 6 in

PROOF

P = 2(12) + 2(6)

P = 24 + 12

P = 36

for this case we must apply distributive property to the following expression:

the distributive property states that:

then, when applying the property we have to multiply the -2 for each term within the parenthesis:

it will take 9 minutes