Geometry and TrigonometryEasyCentre from the equation of a circle
Geometry and Trigonometry practice question
In the xy-plane, which of the following is the centre of the circle x² + y² = 16?
- A. (0, 0)Correct
- B. (4, 4)
- C. (16, 16)
- D. (0, 4)
Answer: A. (0, 0)
x² + y² = r² is centred at the origin; 16 is r².
Why the other answers are wrong
- B. (4, 4)
- (4, 4) is not on the circle or at its centre; 4 is the radius.
- C. (16, 16)
- 16 is r², not a coordinate.
- D. (0, 4)
- (0, 4) is a point on the circle, not its centre.
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