Solving Systems Using Substitution: If the length of the rectangle is twice the width, and the perimeter of the rectangle is 30 cm, what is the length and width of the rectangle?

Answer 1

Let the length be represented by L and width by W

So, L = 2W

and perimeter = 30 cm

Next, use the formula for perimeter of a rectangle ; 2(L+W) to find the measurement of length and width;

Replace L in the formula by 2W from the first equation;

2(2W +W) = 30

Multiply 2 by each item in the parenthesis to get;

4W +2W = 30

6W = 30

Divide both sides by 6 to solve for W;

W=30/6

W= 5

Replace W with 5 in any of the two equations to solve for L;

I'll use L = 2W.

So, L = 2*5

L= 10

Therefore, the length of this triangle is 10cm and width is 5cm.