Question

the length of a rectangle is three times its width.
if the perimeter of the rectangle is 56 in, find its length and width.
length: □ in
width: □ in

Explanation:

Step1: Define variables for width/length

Let width = $w$, length = $3w$

Step2: Use perimeter formula

Perimeter $P=2(\text{length}+\text{width})$, so:
$$56=2(3w + w)$$

Step3: Simplify and solve for $w$

$$56=2(4w) \implies 56=8w \implies w=\frac{56}{8}=7$$

Step4: Calculate length

Length = $3w=3\times7=21$

Answer:

length: 21 in
width: 7 in