How to Find the Area of a Quadrant (a Quarter of a Circle)
A quadrant is a quarter of a circle. So to work out the area of a quadrant, first work out the area of the whole circle (use the formula A = π ×r²) and then divide the answer by 4. Alternatively, you could substitute the radius of the quadrant directly into the formula A = ¼ πr². Let’s take a look at a few examples on working out the area of quadrants:
Example 1
Work out the area of this quadrant (radius 8cm).
Method 1 (using the area of a whole circle and dividing by 4)
First work out the area of the whole circle by substituting the radius of 8cm into the formula for the area of the circle:
A = π ×r²
= π ×8²
= 64π (leave the answer as an exact solution as this need to be divided by 4).
So all you need to do now is divide the answer by 4:
Area of a quadrant = 64π ÷4 = 16π = 50.3 cm² to 3 significant figures.
Method 2 (using ¼ πr²)
Substitute r = 8 directly into the formula A = ¼ πr².
A = ¼ πr².
A = ¼ × π × 8².
A = 50.3 cm²
As you can see it gives exactly the same answer as method 1.
Example 2
Work out the area of this quadrant (radius 3.8m).
Like example 1, begin by substituting the radius of 3.8m into the formula for the area of the circle:
A = π ×r²
= π ×3.8²
= 14.44π (leave the answer as an exact solution as this need to be divided by 4).
Again, all you need to do now is divide the answer by 4:
Area of a quadrant = 14.44π ÷4 = 16π = 11.3 m² to 3 significant figures.
Method 2
Substitute r = 3.8m directly into the formula A = ¼ πr².
A = ¼ πr².
A = ¼ × π × 3.8².
A = 11.3 m²
As you can see it gives exactly the same answer as method 1.
Questions & Answers
- Helpful 1
What is the area of a quadrant with a radius of 6cm, given in terms of Pi?
First square the radius of 6 to give 36.
Now multiply 36 by Pi to give 36Pi
Next, divide the answer by 4 to 9Pi.
Helpful 3Can you find the area of quadrant of a circle whose circumference is 22?
First, find the radius of the circle by dividing the circumfernece by Pi and halving the answer to give 3.501 to 3 decimal places.
Now use 0.25*Pi*radius^2 to give the area of the quadrant 0.25*Pi*3.501^2 = 9.63 to 2 decimal places.
Helpful 11If the area of a circle is 100 cm2, what's the area of one of its quadrants?
All you need to do is divide 100 by 4 to give 25 cm^2.
Helpful 6- Helpful 2
