The width of the rectangle is 25 cm. How much will the area of this rectangle increase if its length is increased from 30 cm to 35 cm.

To solve the problem, you first need to determine the area of a rectangle with a length of 30 centimeters.
To do this, use the following formula:
S = a * b.
Where a and b are the length and width of the rectangle, respectively.
Substituting the numbers, we get:
30 * 25 = 750 cm ^ 2.

In a similar way, we find the area of a rectangle with a side length of 35 cm.
We get:
35 * 25 = 875 cm ^ 2.

Finding the difference.
To do this, subtract the first from the second area.
875 – 750 = 125 cm ^ 2.

Answer.
The area will increase by 125 cm ^ 2.