Similarity test - AA postulate

Objectives
To understand two triangles are similar if any two angles of the triangles are congruent.

Estimated Time
45 minutes

Prerequisites/Instructions, prior preparations, if any

 * 1) The students should know the meaning of the terms congruent and similar.
 * 2) They should understand the terms corresponding sides and angles.
 * 3) They should have an idea of ratio and proportion.

Materials/ Resources needed
Digital resources: Laptop, geogebra file, projector and a pointer

Process (How to do the activity)

 * 1) The teacher can initially have a warm up session regarding terms congruence, similarity and corresponding angles and ratio.
 * 2) She can then project the geogebra file and by moving the sliders she can change the side and angle measures and teach teh AA similarity postulate.
 * 3) Also she can let them understand that in similar triangles, the corresponding sides are proportional.
 * Developmental Questions:
 * 1) What does congruent mean ?
 * 2) What does similarity mean ?
 * 3) How can we test whether the two given figures are similar or not ?
 * 4) In the above two triangles, what measures of both are same ?
 * 5) Identify the corresponding sides and angles.
 * 6) Is their ratio same ?
 * 7) What can you say about the two triangles ?
 * 8) Recall the similarity postulates.
 * 9) By what postulate are the two triangles similar ?
 * Evaluation:
 * 1) Differentiate similarity and congruence.
 * Question Corner:
 * 1) Can the tree and its shadow be considered as similar figures ?
 * 2) Can this similarity concept be used to find the height and depth of objects ? Frame any two of your own questions which can be solved using similarity postulates.