How Many Conditions Are Needed to Specify a Circle?

In summary, three conditions are needed to specify a circle: the center point, the radius, and the plane in which the circle lies. This is because a circle is a two-dimensional shape, meaning it lies on a flat plane. Without these three conditions, the size, position, and orientation of the circle would not be fully defined. While there may be exceptions in certain cases, such as on a curved surface, in most contexts, three conditions are sufficient to specify a circle. It is also possible to define a circle with more than three conditions, such as in 3-dimensional space, but in 2-dimensional space, three conditions are enough.
  • #1
phymatter
131
0
the general equation of a circle has 3 constants , so it is said that 3 conditions , like 3 points (on the circle) are required to specify a circle , but , we require only the center and radius to specify a circle , so how many conditions are actually required ??
 
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  • #2
The center is two pieces of information, an x-coordinate and a y-coordinate, thus three total. If you have x-y coordinates of 3 points, you can write 3 equations with 3 unknowns and solve for the radius and the coordinates of the center.

See this thread:

https://www.physicsforums.com/showthread.php?t=24014
 

1. How many conditions are needed to specify a circle?

The answer is that three conditions are needed to specify a circle: the center point, the radius, and the plane in which the circle lies.

2. Why are three conditions necessary for a circle?

Three conditions are necessary because a circle is a two-dimensional shape, meaning it lies on a flat plane. The center point and radius determine the size and position of the circle, while the plane determines its orientation.

3. Can a circle be specified with less than three conditions?

No, a circle cannot be specified with less than three conditions. Without the center point, the shape would not be a perfect circle. Without the radius, the size of the circle would not be known. And without the plane, the orientation of the circle would not be defined.

4. Are there any exceptions to the rule of three conditions for a circle?

In certain cases, additional conditions may be necessary to specify a circle. For example, if the circle lies on a curved surface rather than a flat plane, the curvature of the surface would need to be taken into account. However, in most mathematical and scientific contexts, three conditions are sufficient to specify a circle.

5. Can a circle be defined with more than three conditions?

Yes, a circle can be defined with more than three conditions. For example, in 3-dimensional space, a circle can be defined with four conditions: the center point, the radius, and two angles to specify the orientation of the circle in 3D space. However, in 2-dimensional space, three conditions are sufficient to define a circle.

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