Similarity, Part 2
A line drawn parallel to one side of a triangle cuts the other two sides in the same ratio. This gives a powerful way to find lengths, and, with areas, scale factors and models, a way to compare sizes.
In this lesson you will
- Use the Basic Proportionality Theorem and its converse to find lengths and test for parallel lines
- Use similar triangles in a trapezium with its diagonals
- Find the ratio of areas of similar triangles from the ratio of sides, and the reverse
- Use a scale factor to convert lengths, areas and volumes between a map or model and the real object