Circle vs Sphere
Circle and sphere are both round in shape but whereas a circle is a figure, a sphere is an object. You can compare the two as a drawing of a tennis ball on a piece of paper and the ball itself in real life. A circle is a 2D figure whereas a sphere is a 3D object having volume. One can only calculate the surface area of a circle whereas it is possible to calculate the volume of a sphere. Earth is considered spherical in nature but when we draw the figure of earth on paper, it is a circle. Some people make the mistake of saying earth is circular in shape which is wrong and they should rather say it is spherical in shape. Here are some more differences between a circle and a sphere.
One thing common in both circles and spheres is that both have a perfect symmetry around their centers. All the points lying at a distance r from the center of the sphere or a circle form a sphere. The longest distance inside a sphere is double this distance r and is called the diameter of the sphere. To a mathematician, both the circle and a sphere are one and the same thing as a collection of all the points that are equidistant ® from the center of the circle or the sphere. In a plane a round object is called a circle but the same circle becomes a sphere in space.
The formulae for a circle are as follows
Circumference= 2 x Pie x r
Area= Pie x r x r
The formulae for sphere are as follows
Surface area= 4 x Pie x r x r
Volume= 4/3 x Pie r x r x r
In brief: • A round object in a plane is a circle while it is a sphere in space • A circle is a 2D figure while a sphere is 3D
