Angle sum property of a quadrilateral

Objectives

Content objectives - what content areas

Skill objectives - what specific skills

Classroom objectives - to demo peer learning, to make a classroom resource, etc -

All these kinds of objectives need not be there for every activity. And no need to list them as different headings. This is only for our reference when we are developing activities.

Estimated Time

40 minutes.

Prerequisites/Instructions, prior preparations, if any

1. The students should have the knowledge of constructing quadrilaterals.
2. They should have the skill of drawing and measuring angles.

Materials/ Resources needed

colour papers, scale , compass, pencil and scissors.

This activity has been taken from the website :http://mathematicsvillage.blogspot.in/search/label/Activity

Process (How to do the activity)

1. Draw a Quadrilateral ABCD on colour chart Sheet .
2. Cut such four Quadrilaterals on four different sheets.
3. Mark <A as <1 , <B as <2 , <C as <3 and <D as <4 on each quadrilateral as shown in fig .
4. Arrange all four angles of quadrilateral one from each colour at one point.
5. What you observe ?
6. It forms a complete angle i.e 360 degrees.
7. This shows that sum of all angles of quadrilateral is 360 degrees.

• Developmental Questions:

1. What is a quadrilateral ?
2. How many angles does a quadrilateral have ?
3. What is the sum of 4 angles of the quadrilateral according to your findings.

• Evaluation:

1. What would be the sum of opposite angles of a quadrilateral ?

• Question Corner:

1. What can you say about the four angles in a regular quadrilateral ? Give an example for regular quadrilateral.
2. Try proving this property in case of concave quadrilaterals as well.