Scale 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.

The scale from the drawing to the actual stop sign is 1 in.: 6 in.

What is the side length of the actual stop sign?

• 11 inches

• 30 inches

• 25 inches

• 12 inches

Answer explanation

To find the scale factor from the drawing to the actual image ask yourself, "What number would I multiply by 1 to get 6?"

What are the dimensions of her scaled copy?

• length: 8 in.

  height: 4.5 in.

• length: 8 in.

  height: 6 in.

• length: 0.5 in.

  height: 0.375 in.

• length: 6 in.

  height: 5.5 in.

Answer explanation

Multiply both the length and width of the original image by the scale factor of 4, then multiply the length and width of the scaled copy to get the area of the scaled copy.

What is the area of the rectangle when it is enlarged by a scale factor of 3?

• 283.5 sq. ft.

• 94.5 sq. ft.

• 31.5 sq. ft.

• 34.5 sq. ft.

Answer explanation

One way to get area of a scaled copy is to get the area of the original image, then multiply that area by the square of the scale factor.

Tim is building a birdhouse. The plans have a scale of 1 inch: 2.5 inches. A rectangular wall of his birdhouse has a drawing length of 2 inches and width of 3 inches. What will the actual area of the wall be?

• 6 sq. in.

• 15 sq. in.

• 37.5 sq. in.

• 22.5 sq. in.

Answer explanation

Find the area of the wall according to the plans. Multiply the area of the wall in the plans by the square of the scale factor to get the area of the wall of the actual birdhouse.

What is the scale factor from ΔDEF to ΔABC?

• 1/2

• 7/3

• 2

• 10/3

If a figure is enlarged by a scale factor of 3, what happens to its area?

• It triples

• It remains the same

• It becomes nine times larger

• It doubles

This is the original shape. What is the AREA of the scaled shape when a scale factor of 2 is applied?

• 15 in²

• 30 in²

• 60 in²

• 16 in²

Scale factor is _________

• the number you multiply the original shape by in order to get the scale copy

• the number you divide the original shape by in order to get the scale copy

• the number you add the original shape by in order to get the scale copy

• the number you subtract the original shape by in order to get the scale copy

Which of the following are scaled copies of the original image? Select ALL that apply

• A

• B

• C

• D