Geometry and TrigonometryEasy–MediumRadius from the centre and a point on the circle
Geometry and Trigonometry practice question
In the xy-plane, a circle has its centre at (3, −2), and the point (3, 4) lies on the circle. What is the radius of the circle?
Answer: 6
The two points share an x-coordinate, so the radius is the vertical distance: 4 − (−2) = 6.
Common wrong answers
- If you answered 2
- 2 subtracts 2 from 4 without minding the sign.
- If you answered 12
- 12 is the diameter.
- If you answered 36
- 36 is the radius squared.
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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