Section 11-3 Perimeters and Areas of Similar Figures

Recall: TT wo polygons are similar iff corresponding angles are congruent and the lengths of corresponding sides are proportional. TT he ratio of the lengths of two corresponding sides of two similar polygons is called the scale factor.

The ratio of the perimeters of two similar polygons is the same as the scale factor.

Areas of Similar Polygons Theorem If two polygons are similar with the lengths of corresponding sides in the ratio, then the ratio of their areas is.

If you are given the ratio of the areas, take the square root of each to find the scale factor or ratio of perimeters.

always, sometimes, or never? 1.Two similar quadrilaterals have the same perimeter. 2.Two squares with the same perimeter are similar. 3.Two regular hexagons are similar. Sometimes Always

always, sometimes, or never? 4.Two right triangles with the same area are similar. 5.Two similar pentagons have the same perimeter. 6.Two rectangles with the same area are similar. Sometimes

always, sometimes, or never? 7.Two regular decagons are similar. 8.Two regular polygons are similar. Always Sometimes