The area of a one is the space occupied through the one in a two-dimensional plane. Alternatively, the an are occupied within the boundary/circumference the a circle is called the area the the circle. The formula because that the area of a circle is A = πr2, where r is the radius that the circle. The unit that area is the square unit, for example, m2, cm2, in2, etc. Area of circle = πr2 or πd2/4 in square units, whereby (Pi) π = 22/7 or 3.14. Pi (π) is the proportion of circumference come diameter of any kind of circle. It is a special mathematical constant.

You are watching: What is the area of a circle with a radius of 12cm?

The area that a one formula is helpful for measuring the region occupied by a circular field or a plot. Suppose, if you have a one table, climate the area formula will aid us come know just how much fabric is needed to cover the completely. The area formula will also help us to understand the boundary length i.e., the one of the circle. Walk a circle have volume? No, a circle doesn't have a volume. A circle is a two-dimensional shape, the does not have actually volume. A circle only has an area and also perimeter/circumference. Allow us find out in detail about the area of a circle, surface ar area, and its circumference v examples.

1.Circle and Parts that a Circle
2.What Is the Area of Circle?
3.Area of one Formulas
4.Derivation of Area of a one Formula
5.Surface Area of one Formula
6.Real-World example on Area the Circle
7.FAQs top top Area the Circle

Circle and also Parts that a Circle


A circle is a collection of clues that room at a fixed distance from the center of the circle. A circle is a close up door geometric shape. We view circles in day-to-day life such as a wheel, pizzas, a circular ground, etc. The measure up of the an are or region enclosed within the one is known as the area of the circle.

*

Radius: The street from the center to a allude on the boundary is referred to as the radius that a circle. That is represented by the letter 'r' or 'R'. Radius plays an essential role in the formula because that the area and circumference that a circle, which we will discover later.

Diameter: A line the passes through the center and also its endpoints lie on the circle is referred to as the diameter that a circle. The is stood for by the letter 'd' or 'D'.

Diameter formula: The diameter formula that a one is twice its radius. Diameter = 2 × Radius

d = 2r or D = 2R

If the diameter that a one is known, that is radius can be calculation as:

r = d/2 or R = D/2

Circumference: The circumference of the circle is equal to the length of that boundary. This method that the perimeter that a circle is equal to that circumference. The size of the rope the wraps around the circle's boundary perfectly will certainly be same to that is circumference. The below-given figure helps you visualize the same. The circumference can be measure by using the given formula:

*

where 'r' is the radius the the circle and also π is the mathematical continuous whose worth is approximated come 3.14 or 22/7. The one of a circle deserve to be provided to uncover the area of that circle.

For a circle v radius ‘r’ and circumference ‘C’:

π = Circumference/Diameterπ = C/2r = C/dC = 2πr

Let us recognize the various parts the a circle utilizing the following real-life example.

Consider a circular-shaped park as shown in the figure below. We can identify the assorted parts the a circle through the aid of the figure and table given below.

*

In a CircleIn our parkNamed by the letter
CentreFountainF
CircumferenceBoundary
ChordPlay area entrancePQ
RadiusDistance indigenous the fountain come the entrance gateFA
DiameterStraight line Distance in between Entrance Gate and Exit Gate through the fountainAFB
Minor segmentThe smaller area of the park, i m sorry is displayed as the beat area
Major segmentThe enlarge area the the park, other than the pat area
Interior component of the circleThe eco-friendly area that the totality park
Exterior part of the circleThe area exterior the border of the park
ArcAny curved part on the circumference.

The area the a circle is the amount of room enclosed within the boundary of a circle. The an ar within the border of the circle is the area occupied by the circle. The may likewise be described as the total number of square devices inside the circle.


The area that a circle can be calculation in intermediate actions from the diameter, and also the circumference of a circle. From the diameter and also the circumference, we can find the radius and then uncover the area of a circle. However these formulae provide the shortest an approach to uncover the area of a circle. Suppose a circle has actually a radius 'r' climate the area of one = πr2 or πd2/4 in square units, where π = 22/7 or 3.14, and also d is the diameter.

Area the a circle, A = πr2 square units

Circumference / Perimeter = 2πr units

Area of a circle can be calculation by utilizing the formulas:

Area = π × r2, wherein 'r' is the radius.Area = (π/4) × d2, where 'd' is the diameter.Area = C2/4π, where 'C' is the circumference.

Examples using Area of circle Formula

Let us think about the complying with illustrations based on the area of one formula.

Example1: If the length of the radius of a one is 4 units. Calculation its area.

Solution:Radius(r) = 4 units(given)Using the formula for the circle's area,Area of a circle = πr2Put the values,A = π42A =π × 16A = 16π ≈ 50.27

Answer: The area that the circle is 50.27 squared units.

Example 2: The size of the largest chord of a one is 12 units. Find the area that the circle.

Solution:Diameter(d) = 12 units(given)Using the formula for the circle's area,Area the a circle = (π/4)×d2Put the values,A = (π/4) × 122A = (π/4) × 144A = 36π ≈ 113.1

Answer: The area the the circle is 113.1 square units.

Area the a Circle making use of Diameter

The area that the one formula in regards to the diameter is: Area that a circle = πd2/4. Here 'd' is the diameter the the circle. The diameter the the circle is twice the radius that the circle. D = 2r. Usually from the diameter, we need to first find the radius that the circle and also then find the area the the circle. V this formula, we can directly find the area that the circle, native the measure up of the diameter of the circle.

*

Area that a Circle using Circumference

The area the a one formula in regards to the circumference is provided by the formula (dfrac(Circumference)^24pi). There space two straightforward steps to find the area of a circle indigenous the offered circumference that a circle. The one of a circle is first used to uncover the radius of the circle. This radius is further useful to uncover the area of a circle. However in this formulae, we will have the ability to directly uncover the area the a circle indigenous the one of the circle.

*

Area of a Circle-Calculation

The area that the circle can be conveniently calculated either from the radius, diameter, or circumference of the circle. The consistent used in the calculate of the area of a circle is pi, and also it has actually a fractional numeric value of 22/7 or a decimal value of 3.14. Any kind of of the values of pi can be used based on the requirement and also the require of the equations. The listed below table mirrors the perform of formulae if we recognize the radius, the diameter, or the circumference of a circle.

Area the a circle as soon as the radius is known.πr2
Area that a circle once the diameter is known.πd2/4
Area that a circle once the circumference is known.C2/

Why is the area that the circle is πr2? To know this, let's first understand just how the formula because that the area that a one is derived.

*

Observe the above figure carefully, if we separation up the circle right into smaller sections and arrange lock systematically it creates a form of a parallelogram. As soon as the one is divided into even smaller sectors, it gradually becomes the shape of a rectangle. The an ext the variety of sections that has an ext it often tends to have actually a form of a rectangle as displayed above.

The area the a rectangle is = length × breadth

The breadth that a rectangle = radius that a circle (r)

When we compare the length of a rectangle and the circumference of a one we can see that the size is = ½ the circumference of a circle

Area of circle = Area that rectangle created = ½ (2πr) × r

Therefore, the area that the circle is πr2, whereby r, is the radius the the circle and also the worth of π is 22/7 or 3.14.


The surface ar area of a one is the very same as the area of a circle. In fact, as soon as we to speak the area of a circle, we median nothing however its full surface area. Surface area is the area lived in by the surface ar of a 3-D shape. The surface of a sphere will be spherical in shape however a one is a an easy plane 2-dimensional shape.

If the length of the radius or diameter or also the circumference of the circle is given, then we can find out the surface area. It is stood for in square units. The surface area of one formula = πr2 where 'r' is the radius that the circle and also the worth of π is approximately 3.14 or 22/7.


Ron and his girlfriend ordered a pizza on Friday night. Each slice was 15 cm in length.

Calculate the area the the pizza the was notified by Ron. You can assume that the length of the pizza part is same to the pizza’s radius.

Solution:

A pizza is one in shape. Therefore we have the right to use the area the a one formula to calculate the area of the pizza.

Radius is 15 cm

Area of circle formula = πr2 = 3.14 × 15 × 15 = 706.5

Area the the Pizza = 706.5 sq. Cm.


Example 4: A wire is in the shape of an it is intended triangle. Every side the the triangle steps 7 in. The wire is bent right into the form of a circle. Discover the area that the circle the is formed.

Solution:

Perimeter that the equilateral Triangle: Perimeter of the triangle = 3 × side = 3 × 7 = 21 inches.

Since the perimeter the the it is intended triangle = one of the one formed.

Thus, the perimeter of the triangle is 21 inches.

Circumference that a one = 2πr = 2 × 22/7 × r = 21. R = (21 × 7)/(44) = 3.34.

Therefore, the Radius of the one is 3.34 cm. Area that a one = πr2 = 22/7 ×(3.34)2 = 35.042 square inches.

Therefore, the area that a one is 35.042 square inches.


Example 5: The time shown in a circular clock is 3:00 pm. The length of the minute hand is 21 units. Uncover the street traveled by the reminder of the minute hand as soon as the time is 3:30 pm.

See more: How High Can Corningware Go In A 450 Degree Oven Safe? Is This Dish Oven

Solution:

When the minute hand is in ~ 3:30 pm, the covers fifty percent of the circle. So, the distance traveled by the minute hand is actually fifty percent of the circumference. Street (= pi) (where r is the size of the minute hand). Hence the distance spanned = 22/7 × 21 = 22 × 3 = 66 units. Therefore, the street traveled is 66 units.