Use Similar Polygons & AA Postulate 6.3 & 6.4 Use Similar Polygons & AA Postulate
SIMILAR POLYGONS Similar Polygons-Same Shape Corresponding angles are congruent Corresponding side lengths are proportional
List all pairs of congruent angles List all pairs of congruent angles. Write the ratios of the corresponding sides.
EXAMPLE List all pairs of congruent angles. Write the ratios of corresponding sides in a statement of proportionality.
Scale Factor If two polygons are similar, then the ratio of the lengths of two corresponding sides is called the scale factor.
Determining Similarity Determine whether the polygons are similar. If they are similar, find the scale factor.
Determine whether the polygons are similar Determine whether the polygons are similar. If they are similar, find the scale factor.
Determine whether the polygons are similar Determine whether the polygons are similar. If they are similar, find the scale factor.
Perimeters of Similar Polygons Perimeter: Sum of the sides of a polygon Ratio of the perimeters = Ratio of corresponding sides Ratio of corresponding lengths=scale factor Altitudes, Medians, Angle Bisectors…
Find the scale factor of the polygon on the left to the one on the right. Find the perimeter of each polygon.
Find the scale factor of the polygon on the left to the one on the right. Find the perimeter of each polygon.
Are the two triangles similar? What do we need to know? Corresponding angles are congruent All corresponding sides have the same proportion Would a simpler way be nice?
Angle-Angle Triangle Similarity If two angles of one triangle are congruent to two angles of another triangle, then the two triangles are similar. This can only be used for triangles!
Determine whether the triangles are similar Determine whether the triangles are similar. If yes, write the similarity statement.
Determine whether the triangles are similar Determine whether the triangles are similar. If yes, write the similarity statement. 1. 2.
Indirect Measurement When given similar triangles, write a proportion to find missing side lengths.