The length of a rectangle is 5 cm less than three times its width. If the perimeter of the rectangle is 54 cm, find the LENGTH of the rectangle.

Answer 1

Hi, Jadyn,

We have two unknows, so look for two equations.

The length (L) is 5 less than the width (W). Line 1

The perimeter is 2*W + 2*L and is 54 cm. Line 2

Substitute line 1 for L into the line 2 equation. That way we can eliminate L and rearrange it on line 4, then solve on line 5. Since we now know W, we can find L via line 6.

I hope this hepls,

Bob

Answer 2

2L + 2W = 54

L= 3W-5

2(3W-5) + 2W = 54

6W -10 + 2W = 54

8W = 64

W = 8 cm

L = 3(8)-5 = 24-5 = 19 cm