Angles associated with parallel lines

Two parallel lines are cut by a transversal  the angles formed are alternate angles, corresponding angles co-interior angles and vertically opposite angles.

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-2.ggb”

Download this geogebra file from this link.

Process (How to do the activity)

• Move the slider to draw a parallel line with the corresponding angles check box unchecked
• How are the two line with each other
• What is the line cutting the two line called
• Bring the slider to initial position : check the corresponding angles check box
• Move the slider to show corresponding angles formed for the two lines
• At the point of intersection of the parallel line and transversal : which other angles are equal
• Is the vertically opposite angle equal to the corresponding angle
• What are alternate angles are they equal
• Evaluation at the end of the activity

1. A minimum of how many corresponding angles should be equal for any two lines to be parallel.
2. How many pairs of corresponding angles are formed when a transversal intersects two parallel lines?
3. How many pairs of alternate angles are formed when  a transversal intersects two parallel lines?