The length of a rectangle is five times the width. The area of the rectangle is 180cm^2. Work out the width of the rectangle.

Lets start off by calling the width of rectangle 'w'. The length of the rectangle is 5 times the width, or '5w'. The area of a rectangle can be worked out by multiplying the length by the width, i.e. 5w x w=5w². We know the area is 180, so we can say 5w²=180. This equation can be solved in two steps. Firstly, we must divide both sides by 5, to give w²=36. Finally, we square root both sides to give w=6. Therefore, the width of the rectangle is 6cm.