Circles and spheres both are circular shapes. As they are circular shapes, that’s why most of the people are confused about these shapes. Most of the people think that circles and spheres are the same shapes. They should know that there is a difference between the sphere and the circle. Its reason is that a circle is a two-dimensional figure. On the other hand, a sphere is a three-dimensional object. These two shapes are different in various ways. That’s why people have to face lots of problems to understand these two shapes. Here, we will discuss the difference between these two shapes.

## What is a Circle?

To form a circle, we have to move a point
around the fixed point at the constant distance. In other words, we can say
that a circle consists of a set of points in the plane. These points are at the
fixed distance from the fixed point. A line that joins the centre of the circle
with any point on the circle is the radius of the circle. In the same circle,
all the radii have the same lengths. A line that joins two points on the circle
is the chord. If a chord passes through the centre of the circle, it is the
diameter of the circle. It means that to find the diameter of a circle, we have
to join two radii. That’s why the length of the diameter of the circle is twice
as that of its radius.

## What is the Sphere?

The three-dimensional form of a circle
is known as a sphere. In a sphere, we have to see all the points on the surface
of the sphere. These points are at an equal distance from the centre of the
sphere. The width and girth of the sphere are constants. The volume of a sphere
is greater. On the other hand, its surface area is smaller. The mean curvature of
the sphere is also constant. Football is the best example of the sphere. There
is no volume of the circle. On the other hand, we can measure the volume of a
sphere by using a formula. In the case of a circle, we can determine its area.
On the other hand, in the case of the sphere, we can determine surface area and
volume.

## Difference between Sphere and Circle

A sphere and a circle are different in various ways. We will try to determine their differences one by one.

### 1. Difference between Definitions of Sphere and Circle

A circle is formed in the form of a
closed curved line. All the points on this closed curved line are at the same
distance. It means that the locus of a point at the fixed length from the fixed
point forms a circle. The fixed point of the circle is its centre. On the other
hand, if we join this fixed point with another point on the circle, it is the
radius of the circle. Similarly, we can also form a sphere by drawing the locus
of a point around the fixed point. Anyhow, it is a three-dimensional object in
the space. To sum up, we can say that a circle is a round object in the plane.
On the other hand, a sphere is a round object in the space.

### 2. Difference between Formulas of Sphere and Circle

To find the area of the circle, we use
the formula **πr ^{2}**. On the other hand, to find the area of
the sphere, we use the formula

**4πr**. As we have discussed earlier that there is no volume of the circle. Anyhow, to find out the volume of the sphere, we use the formula

^{2}**4/3πr**.

^{3}### 3. Dimensions

In the definitions of the circle and
sphere, we have discussed that a circle is a round object in the plane. That’s
why it is a two-dimensional figure. On the other hand, a sphere is a round
object in the space. That’s why it is a three-dimensional object.

### 4. Diameter Formula

The diameters of both circles and
spheres are the same. To find the diameters of the spheres and circles, we use
the formula **2r**. It means that if we
join two points of the circle or sphere with a line that passes through the centre
of the circle or sphere, it forms the diameter of the circle or sphere.

### 5. Circumference Formula

To find the circumference of a circle,
we use the formula **2 π r**.
On the other hand, we can’t find the circumference of the sphere because it
doesn’t have the circumference.

### 6. Equations

Both circles and spheres have the equations.
There is also a difference between the equations of the circles and spheres.
Their equations are given below;

Equation of the circle:

**(x−a) ^{2}+(y−b)^{2}= r^{2}**

Equation of the
sphere is:

**(x−h) ^{2}+(y−k)^{2}+(z−l)^{2}=r^{2}**

### 7. Examples

We can found examples of sphere and
circles in almost all fields of life. Here, we will discuss real-life examples
of circles and spheres. The real-life examples of circles are wheels and coins
etc. On the other hand, the real-life examples of spheres are balls and planets
etc.

### 8. What is it?

While understanding the difference
between the two terms, you should also try to know the answer to this question.
Its reason is that anyone can ask this question about these terms. If someone
asks this question about the circle, you should answer that it is a figure. On
the other hand, if someone asks the same question about the sphere, you should answer
that it is an object.

### 9. Components of Sphere and Circle

In the case of the circle, we can find
out the only area. On the other hand, in the case of the sphere, we can find
the volume along with surface area.

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## Solved Examples Relevant to Sphere and Circle

After understanding the difference
between these two circular
shapes, we can easily solve examples relevant to these circular shapes.

**1. ****What is the area of the circular shape whose
radius is 7 cm?**

Solution:

The radius of the circle = 7 cm

Formula to find the area of the circle
= πr^{2}

After putting the values in this
formula, we will get the answer 153.86 sq. cm.

**2. ****What is the area of a football whose radius is
4 cm?**

Solution:

The radius of the football = 4 cm

Formula
to find the area of the football = 4πr^{2 }

After putting values in this formula, we will get the answer 200.96 sq. cm.

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