Scale factor with Perimeter and Area

Front

What is a scale factor?

Back

A scale factor is a number that scales, or multiplies, a quantity. It is used to enlarge or reduce figures.

Front

If a figure is multiplied by a scale factor of 1/4, how does the perimeter change?

Back

The perimeter will be 1/4 the original perimeter.

Front

How does the area change when a figure is scaled by a factor of 3?

Back

The area will be multiplied by the square of the scale factor. If the original area is 90 km², the new area will be 90 km² * 3² = 810 km².

Front

What happens to a figure when the scale factor is less than 1?

Back

The new figure will be a reduction (shrink).

Front

What is the scale factor from shape A to shape B if shape B is twice the size of shape A?

Back

The scale factor is 2.

Front

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

Back

The figure remains the same size; it is a duplicate copy.

Front

Katherine made a scale drawing of her bedroom with a scale of 1 cm = 3 ft. If the drawing is 9 cm by 9 cm, what is the area of her actual bedroom?

Back

The actual area is 9 cm * 3 ft/cm * 9 cm * 3 ft/cm = 243 ft².

Front

What is the relationship between scale factor and area?

Back

The area of a figure changes by the square of the scale factor.

Front

If a rectangle has an area of 90 km² and is scaled by a factor of 3, what is the new area?

Back

The new area is 90 km² * 3² = 810 km².

Front

What is the perimeter of a figure if the original perimeter is 20 cm and the scale factor is 1/4?

Back

The new perimeter will be 20 cm * 1/4 = 5 cm.