Similar fioures

Seeonthe Fig 29. The two figures look alike but one is a smaller copy of the other. These are similar figures: figures having the same shape but not necessary the same size.

The sides in the same position are the corresponding sides of the figures, and the angles in the same position are the corresponding angles of the figures. For example, A'B' (read A prime B prime) are corresponding sides in the figures above, and ABD and A'B'D' are corresponding angles. The corresponding angles of similar polygons are equal.

If the ratio of side AB to side A'B' is 2:1, then the ratio of a pair of any other two corresponding sides must also be 2:1. The corresponding sides of similar polygons will be parallel if the polygons are placed in the same position.

Rule to Remember: Two polygons are similar if two conditions are satisfied:

1) corresponding sides are proportional;

2) responding angles are equal.