What are similar shapes?
Two shapes are Mathematically Similar if one is an enlargement of the other.
Equivalent Angles in the two shapes will be equal.
Equivalent Lengths in the two shapes will be in the same ratio and are linked by a Scale Factor (which you will normally have to find).
Working with similar shapes
- Identify equivalent known lengths.
- Establish direction (getting bigger or smaller?).
- Find Scale Factor = Second Length ÷ First Length
(Check that SF > 1 if getting bigger and SF < 1 if getting smaller.)
- Use Scale Factor to find length.