A rectangle is 3 times as long as it is wide. The perimeter is 100cm. Find the dimensions of the rectangle. Round to the nearest tenth if necessary. Show all work.

The width is 12.5 and the length is 37.5.

In order to find this, set the width as x and the length as 3x. Now we can multiply them together using the rectangle perimeter formula.

2L + 2W = P

2 (x) + 2 (3x) = 100

2x + 6x = 100

8x = 100

x = 12.5

Now we know the width is 12.5 and we can find the length by multiplying by 3, which is 37.5.