Geometry and TrigonometryEasy–MediumArea from a circumference
Geometry and Trigonometry practice question
A circle has a circumference of 10π. Its area can be written as kπ. What is the value of k?
Answer: 25
2πr = 10π gives r = 5, so the area is 25π.
Common wrong answers
- If you answered 5
- 5 is the radius.
- If you answered 10
- 10 copies the circumference's coefficient.
- If you answered 100
- 100 squares 10, the coefficient of the circumference.
More Geometry and Trigonometry questions
- Easy–Medium
A circle has a radius of 6. What is its area? (Use A = πr².) - Easy–Medium
A right triangle has legs of length 6 and 8. What is the length of the hypotenuse? - Easy–Medium
A circle has a radius of 5. What is its circumference? (Use C = 2πr.) - Easy–Medium
What is the midpoint of the segment joining the points (2, 3) and (8, 11)? - Easy–Medium
What is the measure, in degrees, of angle B? - Easy–Medium
What is the area, in square centimeters, of the trapezoid?
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