The length of the rectangle was increased by 7 centimeters and the width by 13 cm.

The length of the rectangle was increased by 7 centimeters and the width by 13 cm. Determine how the perimeter of the rectangle has changed.

Let us designate the length of the rectangle as “a” and the width as “b” cm.
Let’s calculate the perimeter of the rectangle:
P = 2 * (a + b) = 2a + 2b see.
If the length of the rectangle is increased by 7 cm, it becomes equal to: a + 7 cm.
If its width is increased by 13 cm, it becomes equal to: b + 13 cm.
Let’s calculate the perimeter of the new rectangle:
P = 2 * ((a + 7) + (b + 13)) = 2 * (a + b + 20) = 2a + 2b + 40 cm.
Let’s calculate the difference between the perimeters:
(2a + 2b + 40) – (2a + 2b) = 40 cm.
Answer: The perimeter of the rectangle has increased by 40 cm.