Congruence in triangles – SAS Rule

Objectives

• Compare given sides and angles to check for triangle congruency
• Understand the angle given should be included angle

Estimated Time

30 minutes

Prerequisites/Instructions, prior preparations, if any

Prior knowledge of point, lines, angles, elements of triangle, close figures

Materials/ Resources needed

• Digital : Computer, geogebra application, projector.
• Non digital : Worksheet and pencil.
• Geogebra files : “2.SAS congruency.ggb”

Process (How to do the activity)

• If one side is fixed and an angle is fixed will the two triangles be congruent?
• How many triangles can be possible for a given side and a given angle?
• What is the other parameter that needs to be fixed?
• If two sides are congruent in two triangles will the triangles be congruent.
• Do you need another parameter for the two triangles to be congruent. What other parameter is required - Angle / Side
• If another side is fixed – which rule of congruency does it become?
• Which other angle is required to be fixed for the two triangles to be congruent?
• HW : Construct two triangles with one side and one angle same. Check if they are

Evaluation at the end of the activity

• Students should understand if two sides are given the angle should be included for the triangles to be congruent.
• Students should be able to compare the parameters given to check for congruence