Radius and diameter of a circle

Marking radius and diameter of a circle and understand their relation.

Objectives

1. Radius is a straight line joining centre of a circle to any point on the circumference.
2. Ability to learn the use of compass.
3. Skill of drawing the circle accurately.

Estimated Time

20 minutes

Prerequisites/Instructions, prior preparations, if anyrio

Prior knowledge of points, lines and line segments, formation of a circle.

Materials/ Resources needed

Different coloured papers, compass, scale, pencil and scissors.

Process (How to do the activity)

Instructions to the teacher:

1. The teacher distributes the paper to the students.
2. Shows them how to use compass and draw a circle.
3. Ask every student to make 2 equal parts by folding.
4. What happens if it is folded again to get equal parts?
5. Ask the students to identify the folded lines/marks

Instructions to the student:

1. Draw a circle of given radius.
2. Cut out the circle.
3. Fold the circle into two equal halves.
4. Again fold into further equal halves.
5. Observe and mark the folded line.
6. Identity the diameter and radius.

• Evaluation

1. Was the student successful in marking radius and diameter?
2. Was the student successful in folding and marking?
3. Was the student able to relate radius and diameter.

• Question Corner

1. How many such radii and diameters can be drawn to a given circle?