The length of a rectangle is twice it’s width. the length is 12cm. work out the area of the rectangle

Step-by-step explanation:

As with all word problems we first have to convert it to an equation or equations.

L = length of the Rectangle and W = its width

So L = 2 * W

A = area of the rectangle which is 128 cm^2

So    A = L * W = 128 cm^2

substitute 2W for L from the 1st equation to give    A = 2 * W * W = 2 * W^2 = 128 cm^2

Thus    W^2 = 64 cm^2

finally  W = 8 cm  and therefore  L = 2 * W = 16 cm

The perimeter P = 2 * (L+W) = 2* (8cm + 16cm) = 2 * 24cm = 48 cm

4

step-by-step explanation:

b is the correct answer