Introduction

You are already familiar with some methods for finding the perimeters and areas of simple plane figures, such as rectangles, squares, parallelograms, triangles, and circles, from your earlier classes. Many objects we encounter in our daily lives are related to circular shapes in some form or another — such as cycle wheels, wheelbarrows (thelas), dartboards, round cakes, papads, drain covers, various designs, bangles, brooches, circular paths, washers, and flower beds.

The problem of finding the perimeters and areas of circular figures is of great practical importance. In this chapter, we will begin our discussion with a review of the concepts of perimeter (circumference) and area of a circle and apply this knowledge to find the areas of two special parts of a circular region — the sector and segment.

We will also explore how to calculate the areas of some combinations of plane figures involving circles or their parts.