The length of a rectangular piece of steel in a bridge is 2 meters less than triple the width. The perimeter of the piece of steel is 36 meters. How do you find the length of the piece of steel?

1 Answer
Oct 4, 2015

Length of the Steel piece is "13 m"

Explanation:

Let the width be equal to w meters. The length is 2 meters less than triple the width. So the length of the steel piece is

l = 3w - 2

Now the perimeter of a rectangle is given by

P = 2 * (l + w)" ", where

l is the length
w is the width.

In this case, the perimeter will be

P = 2 * (underbrace(3w - 2)_(color(blue)(=l)) + w)

P = 2 * (4w - 2) = "36 m" -> given

So

2 *(4w - 2) = 36

4w - 2 = 36/2 = 18

4w = 18 + 2 = 20 implies w = 20/4 = "5 m"

The length is

l = 3 * 5 - 2 = "13 m"