Difference between revisions of "1953 AHSME Problems/Problem 11"
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== Solution == | == Solution == | ||
− | + | Call the radius of the outer circle <math>r_1</math> and that of the inner circle <math>r_2</math>. The width of the track is <math>r_1-r_2</math>. The circumference of a circle is <math>2\pi</math> times the radius, so the difference in circumferences is <math>2\pi r_1-2\pi r_2=10\pi</math> feet. If we divide each side by <math>2\pi</math>, we get <math>r_1-r_2=\boxed{5}</math> feet. | |
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==See Also== | ==See Also== |
Revision as of 23:28, 8 April 2020
A running track is the ring formed by two concentric circles. If the circumferences of the two circles differ by feet, how wide is the track in feet?
Solution
Call the radius of the outer circle and that of the inner circle . The width of the track is . The circumference of a circle is times the radius, so the difference in circumferences is feet. If we divide each side by , we get feet.
See Also
1953 AHSC (Problems • Answer Key • Resources) | ||
Preceded by Problem 10 |
Followed by Problem 12 | |
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