Question

A circle has a radius of 3 feet. what is the circumference of a bigger circle if the scale factor of the smaller to bigger is 4:7? Then, what would be the ratio of the circumference from the larger circle to the smaller circle?

Answer 1

• 21π/2 feet
• 7/4

Explanation:

b) The problem statement tells you the ratio of linear dimensions (radius or circumference) is ...

larger/smaller = 7/4

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a) The circumference of the smaller circle is ...

C = 2πr = 2π(3 ft) = 6π ft

Then the circumference of the larger circle is ...

(7/4)(6π ft) = 21π/2 ft . . . . . larger circumference