Proportions/Similar Figure Review (PreAlgebra)

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you find a missing value in a proportion?

Back

Cross-multiply the known values and solve for the unknown.

Front

What is a similar figure?

Back

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

Front

If two triangles are similar, what can you say about their corresponding sides?

Back

The lengths of their corresponding sides are in proportion.

Front

What is the scale factor?

Back

The scale factor is the ratio of the lengths of two corresponding sides of similar figures.

Front

If a painting is enlarged from a width of 3 in. to 15 in., what is the scale factor?

Back

The scale factor is 5 (15 in. / 3 in.).

Front

How do you calculate the actual distance using a scale?

Back

Multiply the distance on the map by the scale factor.

Front

If a shadow of a tree is 4.2 feet and the shadow of a mailbox is 2.8 feet, how do you find the height of the tree?

Back

Set up a proportion using the heights and shadows of both objects.

Front

What is the formula for finding the height of similar triangles?

Back

Height of Tree / Shadow of Tree = Height of Mailbox / Shadow of Mailbox.

Front

What does it mean if two figures are not similar?

Back

It means that their corresponding angles are not equal or their corresponding sides are not in proportion.