Similarity
Overview
Similar shapes are everywhere: a photograph and its enlargement, a model car and the real thing, a map and the landscape it represents. In each case the shape is the same but the size is different, and a single scale factor links every pair of corresponding lengths.
You will learn to identify similar figures, calculate unknown lengths using scale factors, and work with maps and scale drawings. At Higher tier, you will discover that areas scale by the square of the linear factor and volumes by the cube.
Objectives
- Understand and use the geometrical properties that similar figures have corresponding lengths in the same ratio but corresponding angles remain unchanged
- Use and interpret maps and scale drawings
- [Higher] Understand that areas of similar figures are in the ratio of the square of corresponding sides
- [Higher] Understand that volumes of similar figures are in the ratio of the cube of corresponding sides
- [Higher] Use areas and volumes of similar figures in solving problems
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Similarity. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Two similar rectangles have lengths 5 cm and 20 cm. The scale factor is: A) 2 B) 4 C) 15 D) 100 Answer: B
- If the scale factor of two similar shapes is 3, the area scale factor is: A) 3 B) 6 C) 9 D) 27 Answer: C
- A map scale is 1:50 000. What does 4 cm on the map represent? A) 200 m B) 2 km C) 20 km D) 500 m Answer: B
- Two similar solids have a volume ratio of 8:27. The linear scale factor is: A) 2:3 B) 4:9 C) 8:27 D) 3:2 Answer: A
- Shapes are similar if: A) They have the same area B) They have the same perimeter C) Corresponding angles are equal and sides are proportional D) They have the same number of sides Answer: C
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Recommended Books
Practice Mock Questions
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