Area and Perimeter of a Circle

Answer Key(i.)154cm^2.(ii.)616cm^2.(iii.)1386m^2.(iv.)3.14m^2.

Questions:What is the area of a circle if the radius is:(i.)7 cm.(ii.)14 cm.(iii.)21 m.(iv.)1m.

Introduction

Area and Perimeter of a Circle

A circle is a simple shape in Euclidean geometry. It is the set of all points in a plane that are at a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves so that its distance from a given point is constant. The distance between any of the points and the centre is called the radius.A circle is a simple closed curve which divides the plane into two regions: an interior and an exterior.

Circumference = 2πr.Area = π × r ^ 2.Example: What is the area of this circle?Radius = r = 3Area = π × r^2 = π × 32 = π × (3 × 3) = 3.14159... × 9 = 28.27 (upto 2 decimal places)