# Parallel lines

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Relation between angles that are formed in multiple parallel lines is investigated with geogebra sketch.

### Objectives

To understand corresponding angles are equal

To understand alternate angles are equal

### 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 : Parallellines-3.ggb

Download this geogebra file from this link.

### Process (How to do the activity)

- Use the file to seek the initial observations from children – number of lines, are the lines parallel, line that acts as a transversal.
- Ask how many angles are there present. List all the angles formed.
- Additional information can be retrieved – no of angles are formed at each point, number of angle pairs, number of linear pairs at each point.
- Talk about supplementary angle pairs – let them identify the supplementary angle pairs for the parallel lines.
- Move the transversal using point D to observe the changes made by the transversal with the parallel lines.
- Children can observe the pair of angles that vary equally
- Mention corresponding angles and their properties
- For a give pair of parallel lines list all the corresponding angles.
- Use point B to show that lines need not be parallel with x-axis to be parallel with each other.
- Inquire about number of parallel lines that can be drawn for a given line.

- Change the position of point D to record other values

Angle BPD Angle DPQ Total Angle KMP Angle PMN Total Angle ECM Angle MCL Total .

**Evaluation at the end of the activity**