ABSTRACT
At the end of this chapter, you should be able to:
• define a circle • state some properties of a circle – including radius, circumference, diameter, semicircle, quadrant, tangent,
sector, chord, segment and arc • appreciate the angle in a semicircle is a right angle • define a radian, and change radians to degrees, and vice versa • determine arc length, area of a circle and area of a sector of a circle • state the equation of a circle • sketch a circle given its equation • understand linear and angular velocity, performing simple calculations • appreciate centripetal force and acceleration, performing simple calculations
A circle is a plain figure enclosed by a curved line, every point on which is equidistant from a point within, called the centre. In Chapter 27, worked problems on the areas of circles and sectors were demonstrated. In this chapter, properties of circles are listed and arc lengths are calculated, together with more practical examples on the areas of sectors of circles. In addition, the equation of a circle is explained and application to linear and angular velocity and centripetal force and acceleration are explored.
