Difference between revisions of "Sum of the interior angles of a quadrilateral"
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* In the geogebra sketch for the quadrilateral measure the sides and angles at the vertices | * 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 | * Calculate the sum of these angles of the quadrilateral? Note your observations | ||
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| − | + | |Quadrilateral | |
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| + | |Angle1 | ||
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| + | |Angle3 | ||
| + | |Angle4 | ||
| + | |Angle1+Angle 2+ Angle3 + Angle 4 | ||
| + | |Whatdo you observe about their sum | ||
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| + | |Q2 | ||
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| + | |Q3 | ||
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* Draw any one diagonal. What do you notice? What is the quadrilateral divided into? How many triangles are formed? | * 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? | * What is the measure of the sum of angles in each quadrilateral? So what is the measure of all the angles of the quadrilateral? | ||
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|Angle 2 | |Angle 2 | ||
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Angle 3 | Angle 3 | ||
|Sum of angles | |Sum of angles | ||
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|Angle 2 | |Angle 2 | ||
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Angle 3 | Angle 3 | ||
|Sum of angles | |Sum of angles | ||
Revision as of 06:12, 16 April 2019
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
| 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
| Observation | Triangle1 | Triangle2 | Sum of angles of two triangle | ||||||
| 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.