The length of the rectangle is 12 cm longer than its width. If the length is increased by 3 cm and the width by 2 cm
The length of the rectangle is 12 cm longer than its width. If the length is increased by 3 cm and the width by 2 cm, then the area of the rectangle will increase by 80 cm2. Find the length and width of the rectangle.
1. Let the width be x centimeters.
2. Let’s calculate the length.
(x + 12) centimeters.
3. What is the area of the rectangle?
x * (x + 12) = (x² + 12x) cm².
4. Find out the new size of the sides.
a) The length is x + 12 + 3 = (x + 15) centimeters.
b) Width (x + 2) centimeters.
5. Let’s find its area.
(x + 15) * (x + 2) = x² + 2x + 15x + 30 = (x² + 17x + 30) cm²;
6. To determine the width, compose an equation.
x² + 17x + 30 – x² – 12x = 80;
5x = 50;
x = 50/5 = 10;
x = 10 centimeters.
7. The length of the rectangle is.
x + 12 = 10 + 12 = 22 centimeters.
Answer: 10 and 22 centimeters.