Similar Figures & Scale Factor

Front

What are similar figures?

Back

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 a scale factor?

Back

A number that describes how much a figure is enlarged or reduced. It is the ratio of the lengths of corresponding sides of similar figures.

Front

If the scale factor is greater than 1, what happens to the figure?

Back

The figure gets larger.

Front

If the scale factor is less than 1, what happens to the figure?

Back

The figure gets smaller.

Front

How do you determine if two figures are similar?

Back

Two figures are similar if their corresponding angles are equal and the lengths of their corresponding sides are proportional.

Front

What is the scale factor if a side of a smaller figure is 3 cm and the corresponding side of a larger figure is 6 cm?

Back

The scale factor is 2.

Front

What is the measure of angle X if two similar triangles have angles of 60° and 120°?

Back

Angle X is 60°.

Front

If triangle A has sides of 4 cm, 6 cm, and 8 cm, and triangle B has sides of 2 cm, 3 cm, and 4 cm, are they similar?

Back

Yes, they are similar with a scale factor of 0.5.

Front

What is the scale factor if a rectangle's length increases from 5 cm to 10 cm?

Back

The scale factor is 2.

Front

If two similar figures have a scale factor of 1.5, what is the ratio of their areas?

Back

The ratio of their areas is 1.5² = 2.25.