Proportions

Ratio is a comparison of two quantities.

Proportion is two equal ratios.

Similar Polygons have congruent angles and corresponding sides are proportional.

Identifying Similar Triangles:

AA If two angles of one triangle are congruent to two angles of another triangle, then the triangles are similar.

SSS If the corresponding sides are proportional then the triangles are similar.

SAS If two corresponding sides are proportional and the included angles are congruent then the triangles are similar.

Triangle Proportionality:

Angle Bisector is a proportional with the sides also.

Median property

Example Problems

Solve the proportions:

1.               2.           3.

Use proportions to solve:

4. If Jamie drives 264 miles in 4 hours, how many miles can she
    drive in 20 hours?

5. If 1.3 cm on a blueprint represent 20 miles, how wide is a lake
     measuring 6.4cm?