Last modified on August 3rd, 2023

chapter outline

 

Quadrant of a Circle

Quadrant refers to the four quarters in the coordinate plane system. Each of the four sections is called a quadrant. Let’s learn what it means in a circle is.

What is Quadrant of a Circle

A quadrant of a circle is each of the quarter of a circle. It is thus a sector of 90 degrees. All four quadrants are of equal size and area. Thus, when four quadrants are joined together, it forms a circle.

Quadrant of a Circle

In the above figure, the region highlighted as ABO is one of the quadrants of the given circle and the angle AOB makes a right angle at its center.

Formulas

Area of a Quadrant of a Circle

As we know, all four quadrants have the same area. Thus calculating the area of one of the quadrants will give us the area f the other three.  Also, multiplying the area of a quadrant by 4 will give us the area of the circle. Now, let us find the formula to find the area of a single quadrant.

To calculate the area of a quadrant of a circle, we should know the area of a circle. As an area of a quadrant is a quarter of the total area of the circle, we can derive the formula to calculate the quadrant of a circle as follows:

As we know, the formula to calculate the area of a circle is given as:

Area (A) = πr2, here π = 3.141 = 22/7, r = radius

Now, dividing the above formula by 4 will give the area of the quadrant of a circle,

Thus,

Area (A) of a quadrant of a circle = πr2/4

Area of Quadrant of a Circle Formula

The area of the quadrant of a circle is expressed in square units.

Let us solve a problem involving the above formula.

Find the area of a quadrant of a circle with a radius of 12 m. (Assume π = 3.141)

Solution:

As we know,
Area (A) = πr2/4, here π = 3.141, r = 12 m
= (3.141 × (12)2/4) m2
= 113.07 m2
Thus, the area of a quadrant of a circle with a radius of 12 m is113.07 m2

Perimeter of a Quadrant of a Circle

The perimeter of a quadrant of the circle is one-fourth of the circumference and twice the radius of the circle. It is also called the circumference of the quadrant of a circle. The formula to calculate the perimeter of a quadrant of a circle is derived below:

As we know, the formula to calculate the perimeter of a circle is given as:

Perimeter (P) = 2πr, here π = 3.141 = 22/7, r = radius

Now, dividing the above formula by 4 and adding it to twice the radius of the circle, will give the perimeter of the quadrant of a circle

Thus,

Perimeter (P) of a quadrant of a circle = 2πr/4 + 2r, which can be simplified as:

Perimeter (P) of a quadrant of a circle = πr/2 + 2r = r(π/2 + 2)

Perimeter of Quadrant of a Circle Formula

Let us solve some problems involving the above formulas.

Find the perimeter of the quadrant of a circle with a radius of 22 cm.

Solution:

As we know,
Perimeter (P) = r(π/2 + 2), here π = 3.141, r = 22 cm
= [22(3.141/2 + 2)] cm
= [(34.55 + 44)] cm
= 78.55 cm
Thus, the perimeter of the quadrant of a circle with a radius of 22 cm is 78.55 cm

Find the circumference of the quadrant with a radius of 6.2 cm.

Solution:

As we know,
Circumference is the other name of the perimeter of a circle.
Perimeter (P) = r(π/2 + 2), here π = 3.141, r = 6.2 cm
= 6.2(3.141/2 + 2)
= 22.13 cm
Thus, the circumference of the quadrant of a circle with a radius of 6.2 cm is 22.13 cm

The perimeter of a sheet of paper in the shape of a quadrant of a circle is 15 cm. Find its area. (Use π = 3.141).

Solution:

As we know,
Perimeter (P) = r(π/2 + 2), here P = 15 cm, π = 3.141
=> 15 = r(3.141/2 + 2)
=> 15 = r × 3.57
=> r = 15/3.57 = 4.20 cm
Now, as we know
Area (A) = πr2/4, here π = 3.141, r = 4.20 cm
= [3.141 × (4.20)2/4]
= 13.85 cm2
Thus, the area of a sheet of paper in the shape of a quadrant of a circle with a perimeter of 15 cm is 13.85 cm2

FAQs

Q1. What fraction of a circle is a quadrant?

Ans. Quarter.

Last modified on August 3rd, 2023

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