In the figure above, the radius is 5, and the measure of the central angle is 72°.
The arc length is of the circumference:
Area: The area of a circle is usually found using this formula in terms of the
radius r:
Area of a Circle = πr^2The area of the circle above is π(4)^2 = 16π.
Area of a sector: A sector is a piece of the area of a circle. If n is the degree
measure of the sector’s central angle, then the area formula is