CEMC's Open Courseware - Lesson 9: Similar Triangles

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- Watch
- - Try This
  - Angle-Angle Similarity
  - Side-Side-Side Similarity
  - Side-Angle-Side Similarity
  - Constructing Similar Triangles
  - Alternative Format
- Review
- - Question 1
  - Question 2
- Practise
- - Exercises
  - Answers and Solutions
- Question Descriptions

Question Descriptions

This page gives brief descriptions of all of the questions that have been embedded in the lesson slideshows, and is intended primarily for teachers. For some questions, links to third-party websites are provided for your convenience.

Angle-Angle Similarity

Check Your Understanding 1

Interactive question. Students are given two triangles with all side lengths except one, and the measures of two angles. They are told the triangles are similar by the AA similarity rule. First they are asked to match the corresponding sides, and then they are asked to find the value of the missing side length.
Online: https://ggbm.at/RuqyhrM3

Side-Side-Side Similarity

Explore This 1

Interactive question. Students are given two triangles that are in the same proportion using a given scale factor. Students can move a slider to change the scale factor. As they do this, the angle measurements and side lengths for both triangles are shown, so students can verify the triangles are similar.
Online: https://ggbm.at/zucQbXeh

Check Your Understanding 2

Interactive question. Students are given a triangle with all side lengths and angles given. They are also given some information about another triangle and are asked whether or not the triangles are similar. If they are similar, the students will need to decide if they are similar by the SSS rule or the AA rule.
Online: https://ggbm.at/JnWZHYK8

Side-Angle-Side Similarity

Explore This 2

Interactive question. Students are given two triangles that are in the same proportion using a given scale factor. Students are also told the triangles have one angle in common. Students can move a slider to change the scale factor. As they do this, the other two angle measurements and side lengths for both triangles are shown, so students can verify the triangles are similar.
Online: https://ggbm.at/rAjdxy3e

Check Your Understanding 3

Interactive question. Students are given a triangle with all side lengths and angles given. They are also given some information about another triangle and are asked whether or not the triangles are similar. If they are similar, the students will need to decide if they are similar by the SSS rule, the SAS rule, or the AA rule.
Online: https://ggbm.at/ybMx3nAP

Constructing Similar Triangles

Check Your Understanding 4

Interactive question. Students are given two triangles that share a vertex as well as the lengths of the two sides enclosing the vertex. They are asked to draw a triangle with a given scale factor.
Online: https://ggbm.at/VfYvDRse