2010 AMC 10A Problems/Problem 5
Problem 5
The area of a circle whose circumference is is . What is the value of ?
Solution
If the circumference of a circle is , the radius would be . Since the area of a circle is , the area is . The answer is .
Solution 2
By definition, is the ratio of the circumference to the diameter. Since the circumference is , the diameter must be and the radius is . Therefore, by the area of circle formula the area is and .
Video Solution
https://youtu.be/C1VCk_9A2KE?t=290
~IceMatrix
See Also
2010 AMC 10A (Problems • Answer Key • Resources) | ||
Preceded by Problem 4 |
Followed by Problem 6 | |
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