7.3.2.2 Scale Factor

Front

What is a scale factor?

Back

A scale factor is a number that scales, or multiplies, a quantity. It is used to determine how much larger or smaller a figure is compared to another figure.

Front

If triangle ABC is similar to triangle XYZ, what does that mean?

Back

It means that the corresponding angles of the triangles are equal and the lengths of corresponding sides are proportional.

Front

How do you find the scale factor between two similar figures?

Back

To find the scale factor, divide the length of a side of one figure by the length of the corresponding side of the other figure.

Front

What is the scale factor from a triangle with sides 2, 3, and 4 to a triangle with sides 4, 6, and 8?

Back

The scale factor is 2, since each side of the second triangle is twice the length of the corresponding side of the first triangle.

Front

If the scale factor is 3/4, what does that mean for the size of the figure?

Back

It means the new figure is 3/4 the size of the original figure.

Front

What is the scale factor from a large triangle to a small triangle if the sides are 6 and 4?

Back

The scale factor is 2/3, since 4 divided by 6 equals 2/3.

Front

If a television has a length of 50 inches and a similar television has a length of 108 inches, what is the scale factor?

Back

The scale factor is 108/50 or 2.16.

Front

What is the width of a second television if the first has a width of 21 inches and the second has a length of 108 inches?

Back

The width of the second television is 45.36 inches.

Front

Are two figures with a scale factor of 1 similar?

Back

Yes, if the scale factor is 1, the figures are identical and therefore similar.

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 proportional.