The area of the rectangle is 48 cm2. What is the length and width of a rectangle if the length is 3 times its width?

Let the width of the rectangle be x (x) cm, then the length is (x • 3) cm. Substitute these values of the width and length in the formula for finding the area (S = a • b) and solve the equation:
x • x • 3 = 48;
x² • 3 = 48;
x² = 48: 3;
x² = 16;
x = √16;
(1) x = 4
(2) x = – 4 – does not satisfy the condition of the problem, since the width cannot have a negative value.
Let’s calculate the length: x • 3 = 4 • 3 = 12 (cm).
Answer: the width of the rectangle is 4 cm and the length is 12 cm.