Sum of the interior angles of a quadrilateral
Revision as of 06:09, 16 April 2019 by Preeta (talk | contribs) (→Process (How to do the activity))
Objectives
- To establish that sum of interior angles of any quadrilateral is 360o
Estimated Time
40 minutes
Prerequisites/Instructions, prior preparations, if any
Prior knowledge of point, lines, angles, intersecting lines, vertically opposite angles, properties of triangle
Materials/ Resources needed
- Digital: Computer, geogebra application, projector.
- Non digital : Worksheet and pencil
- Geogebra files : ‘Sum of the interior angles of a quadrilateral.ggb’
Process (How to do the activity)
- In the geogebra sketch for the quadrilateral measure the sides and angles at the vertices
- Calculate the sum of these angles of the quadrilateral? Note your observations
- {| class="wikitable" |Quadrilateral |Side1 |Side2 |Side3 |Side4 |Angle1 |Angle2 |Angle3 |Angle4 |Angle1+Angle 2+ Angle3 + Angle 4 |Whatdo you observe about their sum |- |Q1 | | | | | | | | | | |- |Q2 | | | | | | | | | | |- |Q3 | | | | | | | | | | |}
- Draw any one diagonal. What do you notice? What is the quadrilateral divided into? How many triangles are formed?
- What is the measure of the sum of angles in each quadrilateral? So what is the measure of all the angles of the quadrilateral?
- Make different quadrilaterals. Divide it into two triangles, measure the angles of the two triangles, check their sum.
- Tabulate the angles of the two triangles {| class="wikitable" |Observation | colspan="4" |Triangle1 | colspan="4" |Triangle2 |Sum of angles of two triangle Triangle1 + Triangle2 |- | |Angle 1 |Angle 2 | Angle 3 |Sum of angles |Angle 1 |Angle 2 | Angle 3 |Sum of angles | |- |Q1 | | | | | | | | | |- |Q2 | | | | | | | | | |- |Q3 | | | | | | | | | |}
Evaluation at the end of the activity
- Is the sum of any quadrilateral 360o.