Scale Factors and Area

What is the scale factor of her drawing?

• 10/6

• 2/6

• 3/5

• 1.75

Answer explanation

The scale ratio from the original image to the drawing is written as 6 cm/10 cm. Simplify this ratio and drop the units to get the scale factor. Check the reasonableness of your answer. The scaled copy is smaller than the original image so the scale factor must be less than one.

What is the area of the rectangle if reduced by a scale factor of 1/8?

• 72 sq. cm.

• 1,152 sq. cm.

• 144 sq. cm.

• 18 sq. cm.

Answer explanation

Multiply the length and width of the original rectangle by the scale factor to get the dimensions of the scaled copy. Multiply the length and width of the scaled copy to find the area.

What is the scale factor from the original image to the scale drawing?

• 2

• 0.5

• 1/4

• 3

Answer explanation

The scaled copy is smaller than the original image so the scale factor from the original image to the scaled copy must be less than one.

What is the scale factor from the original image to the scale drawing?

• 1.5

• 0.6

• 2/3

• 0.4

Answer explanation

The scaled copy is larger than the original image so the scale factor from the original image to the scaled copy must be greater than one.

If the scale factor is 4, what is the measurement of x?

• 20 m

• 24 m

• 16 m

• 4 m

The two rectangles are scale drawings. What is the measurement of x?

• 21

• 1.25

• 20

• 4

In the figure above, a dilation from A to A' has occurred. What is the scale factor?

Mathematical Equivalence

ON

Quadrilateral NDMP was dilated to make N'D'M'P'. What was the scale factor?

• 2

• 3

• 1/3

• 1/2

If the scale factor is 4, what is the measurement of x?

• 20 m

• 24 m

• 16 m

• 4 m

Choose the correct scale factor:

• 2

• 3

• 1/3

• 1/2