Introduction to quadrilaterals
Objectives
- To make quadrilateral
- Measure sides – segment lengths
- Measure interior angles and find their sum
- Measure length of diagonals and angle between diagonals
Estimated Time
30 minutes
Prerequisites/Instructions, prior preparations, if any
Prior knowledge of point, lines, angles, intersecting lines, vertically opposite angles
Materials/ Resources needed
- Digital : Computer, geogebra application, projector.
- Non digital : worksheet and pencil.
- Geogebra files : 'Introduction to quadrilaterals.ggb'
Process (How to do the activity)
- What is a quadrilateral? How many line segments are required for a quadrilateral. How many vertices in a quadrilateral? How many interior angles ?
- How many lines can be drawn such that they join opposite vertices in a quadrilateral?What are these lines called?
- Diagonals divide the quadrilateral into which shape? How many triangles are formed?
- Do the two lines intersect with each other? At the point of intersection how many angles are formed?Do you notice any equal angles? What kinds of angle pairs are formed at the point of intersection?
- Note the angle measures at the diagonals. Calculate the sum of these angles. Analyze the sum of angles measure at the point of intersection.
- Draw different quadrilaterals and to measure the angles at the point of intersection,calculate the sum of these angles.
| Quadrilateral | Side1 | Side2 | Side3 | Side4 | Angle1 | Angle2 | Angle3 | Angle4 | Angle 1+Angle 2+ Angle3 + Angle 4 | What do you observe about angles around diagonal |
| Q 1 | ||||||||||
| Q 2 | ||||||||||
| Q 3 | ||||||||||
| Q 4 |