Vertically opposite angles

Name of the activity
Brief blurb describing what the activity. If this has been borrowed from some external web site (for example, a non OER or OER site which had this idea and based on which the activity was developed)

Objectives
Introduce children to concept of supplementary angles

Estimated Time
30 minutes

Prerequisites/Instructions, prior preparations, if any
Prior knowledge of point, lines, angles

Materials/ Resources needed

 * Digital : Computer, geogebra application, projector.
 * Non digital : Worksheet and pencil.
 * Geogebra files : “Vertically opposite angles.ggb”

Process (How to do the activity)

 * 1) Prior hands on activity (optional – children can use 2 strips newspaper or sticks to form vertically opposite angles and note the changes in the angles with change in the position of the strips or sticks).
 * 2) Students to identify number of angles formed when the two lines cross each other
 * 3) Name the all the angles formed around the point
 * 4) Do the angles formed have a relation
 * 5) Identify angles on AB: what do the form together
 * 6) Identify angles on CD: what do they form together
 * 7) What is observed about these angle pairs on the two lines
 * 8) Can you find other pair of angles on line AB and CD
 * 9) What is common about these angles
 * 10) Record the values of the angles formed and their sum in the worksheet
 * {| class="wikitable"

Sl No. Value ofslider α
 * rowspan="2" |
 * rowspan="2" |
 * colspan="2" |Angles on line AB
 * rowspan="2" |∠DOA+ ∠BOD
 * colspan="2" |Angles on line CD
 * rowspan="2" |∠ DOA+∠AOC
 * rowspan="2" |Common angle the lines share
 * ∠ DOA
 * ∠ BOD
 * ∠ DOA
 * ∠ AOC
 * }
 * Evaluation at the end of the activity
 * 1) What is the angle measure of the sum of any two adjacent angles when two lines intersect?
 * 2) What is the total measure of all the angles formed when two lines intersect?
 * }
 * Evaluation at the end of the activity
 * 1) What is the angle measure of the sum of any two adjacent angles when two lines intersect?
 * 2) What is the total measure of all the angles formed when two lines intersect?
 * }
 * Evaluation at the end of the activity
 * 1) What is the angle measure of the sum of any two adjacent angles when two lines intersect?
 * 2) What is the total measure of all the angles formed when two lines intersect?
 * Evaluation at the end of the activity
 * 1) What is the angle measure of the sum of any two adjacent angles when two lines intersect?
 * 2) What is the total measure of all the angles formed when two lines intersect?