The perimeter of the rectangular sports hall is 110 m. The width of the hall is 25 m. Find the area of the hall.

Let’s write a formula to calculate the perimeter of a rectangle:
2 * (a + b) = P, where a is the width of the rectangle, b is the length of the rectangle.
Substituting into the original formula, we get: 2 * (a + 25) = 110.
Let’s solve the equation, find the width of the rectangle: 2a + 50 = 110.
2a = 110 – 50 = 60.
a = 60/2 = 30 m.
Let us now find the area of a rectangular sports hall: S = a * b = 25 * 30 = 750 m².
Answer: the area of a rectangular sports hall is 750 m².