Question

Figure A is reduced of figure B.

a). what is the scale factor?
b). if A has area 15cm2. find the area of B.
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Answer 1

Part A

Answer: 3/5

Reason:

Divide the side lengths of B over A to get B/A = 3/5. The order is important. The fraction 3/5 is smaller than 1 to indicate a size reduction. There are no units involved with the scale factor.

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Part B

Answer: 5.4 square cm

Reason:

The linear scale factor is 3/5. The area scale factor is (3/5)^2 = 9/25. It means if figure A had area 25, then figure B would have area 9.

Let's use that idea to set up the following:

(area of figure B)/(area of figure A) = 9/25

B/A = 9/25

x/15 = 9/25

25x = 15*9

25x = 135

x = 135/25

x = 5.4 represents the area of figure B