Question

The circumference of a circle measures 22π units. Find the number of square units in the area of the circle. Express your answer in terms of π.

Answer 1

A = 11²/{4π}

Explanation:

The circumference equation is C = 2πr. Thus, r = C / (2π), and:

C² (22π)² 2²11²π² 11²

r² = ---------- so, if C = 22π units, r² = -------------- = ---------------- = -------------

(2π)² (2π)^4 (2π)²(2π)² (2π)²

11²π²

or r² = ---------------

The area equation for a circle is A = πr² which here is π·11²/(2π)²

This reduces to 11²/{4π}