Arc of a circle

The part of the circumference within the two points in either directions are called its arcs.

Objectives

1. The students learn that an arc is a part of a circle included between two distinct points on the circumference of the circle.
2. The students learn that the the larger arc is called major arc and the smaller one is called minor arc.

Estimated Time

10 minutes

Prerequisites/Instructions, prior preparations, if any

1. The students should know to draw a circle using compass.
2. They should know that arc is part of the circumference.

Materials/ Resources needed

• Digital : Computer, geogebra application, projector.
• Non digital : Worksheet and pencil, compass, strings
• Geogebra files : Arcs in a circle .ggb

Process (How to do the activity)

• • If the circle is divided into 2 parts?
  • How many arcs are formed?
  • Are the two arcs equal?
  • Establish minor arc(smaller arc) and major arc(larger arc)
  • Compare region enclosed by major arc and minor arc, which is larger?
  • Establish sector – major sector and minor sector
  • Animate the geogebra file to show a major arc becomes a minor arc.
  • If one is major arc, the other is a minor arc; can the two arcs be equal?What are they called?
  • How are the two points with respect to center of the circle when arcs are equal.
  • If the angle between the radii is fixed but radius of the circle is increased, what can you say about the two arcs?
• Evaluation

1. What is the longest arc of a circle called?
2. What are the arcs called when both major and minor arcs are of same size?