These reflected rectangles are example of congruent shapes. When transforming a shape, either through translation, reflection or rotation, a congruent shape is produced. Enlargements create shapes ...

New work on the problem of “scissors congruence” explains when it’s possible to slice up one shape and reassemble it as another. If you have two flat paper shapes and a pair of scissors, can you cut ...

Prove two triangles are congruent by showing they satisfy one of four criteria. Find missing lengths by using the scale factor. The relationship between similar shapes may be expressed as a ratio.