👉 In mathematics, a barrelage is defined as the area enclosed by two concentric circles. The formula for the circumference of a circle is 2πr, where r is the radius of the circle. Therefore, the formula for the circumference of a circle with a given radius (r) can be expressed as: Circumference = 2πr The formula for the area of a circle is πr², where r is the radius of the circle. Therefore, the formula