The length of a rectangle is equal to triple the width. Which system of equations can be used to find the dimensions of the rectangle if the perimeter is 86 centimeters?

Answer 1

Let L = length, W = width and P = perimeter

L = 3W

P = 86 = 2(L + W)

Answer 2

Perimeter is the distance around the outer edge of the rectangle.

The rectangle has 2 lengths (L) and 2 widths (W), so the perimeter equation is

P=2L + 2W =86

divide both sides, everything on both sides, by 2, and one of your equations in the system of equations is

L + W = 43

The other is that the length (L) is (=) triple (3 times) the width (W).

In math-speak, this other equation for your system of equations is

L=3W

Then can substitute L=3W into the "L" in L+W=43,

then solve for W,

multiply your answer for W by 3 and get L