12.9 Similar Figures

Front

Define similar figures.

Back

Two figures that have the same shape but may differ in size. Their corresponding angles are equal, and their corresponding sides are in proportion.

Front

What is the ratio of the sides of similar figures?

Back

The ratio of the lengths of corresponding sides of similar figures is constant.

Front

If two triangles are similar, what can be said about their angles?

Back

All corresponding angles of similar triangles are equal.

Front

If triangle ABC is similar to triangle DEF, and the length of side AB is 4 cm and side DE is 8 cm, what is the ratio of their sides?

Back

The ratio of their sides is 1:2.

Front

What is the relationship between the perimeters of similar figures?

Back

The ratio of the perimeters of similar figures is the same as the ratio of their corresponding side lengths.

Front

If the sides of two similar rectangles are in the ratio 3:5, what is the ratio of their areas?

Back

The ratio of their areas is 3²:5² or 9:25.

Front

Solve for x: If triangle ABC is similar to triangle DEF, and AB = 6 cm, DE = x cm, and the ratio of similarity is 2:3, what is x?

Back

x = 9 cm.

Front

What does it mean for two figures to be congruent?

Back

Two figures are congruent if they have the same shape and size.

Front

If two similar figures have a side length ratio of 1:4, how does this affect their area?

Back

The area ratio will be 1²:4² or 1:16.

Front

Find the missing side length: Triangle ABC is similar to triangle DEF. If AB = 5 cm and DE = 15 cm, what is the length of side EF if BC = 8 cm?

Back

EF = 24 cm.