Difference between Circle and Sphere

Distinguish, differentiate, compare and explain what is the Difference between Circle and Sphere. Comparison and Differences.

Circle

A circle is formed by a point moving around a fixed point (the centre) at a constant distance. A circle is the set of all points in the plane that are a fixed distance (the radius) from a fixed point (the centre).

Any interval joining a point on the circle to the centre is called a radius. By the definition of a circle, any two radii have the same length.

An interval joining two points on the circle is called a chord.

A chord that passes through the centre is called a diameter. Since a diameter consists of two radii joined at their endpoints, every diameter has length equal to twice the radius.

Sphere

A sphere is a three-dimensional form of a circle, where all points on the surface of the sphere are at a constant distance from the centre of the sphere.

The Earth is not exactly a sphere. A grapefruit is a better analogy, as it is flatter at the top and bottom (an oblate sphere). The diameter as measured through the North and South Poles is about 40 km less than the diameter using two points on the Equator. The radius of the Earth is usually given as 6 370 kilometers.