Find the area of a circle whose diameter is 12.6 dm.

We are given a circle with a diameter of 12.6 decimeters. We need to find the area of a circle with a given radius.

Let’s remember the formula for finding the area of a circle in terms of diameter.

S = 1 / 4πd ^ 2, where π is a constant whose value is 3.14, and d is the diameter of the circle.

It remains for us to substitute the values of the diameter and the number π in the formula, and make calculations.

S = 1/4 * 3.14 * 12.6 ^ 2 = 1/4 * 3.14 * 158.76 = 124.6266 = 124.63 dm2.

So, the area of a circle with a diameter equal to 12.6 dm is equal to 124.63 dm2.

Answer: 124.63 dm2 is the area of a circle with a diameter of 12.6 dm.