AREA OF A CIRCLE
Definition Of Area Of A Circle
Area of a Circle is the amount of space occupied by the circle.
More About Area of a Circle
Area of a circle of radius r is given by = πr2.
Examples of Area of a Circle
Diameter = 12 cm, radius = 
= 
= 6 cm.
Area of a circle = πr2 = π(6)2 = 36π cm2 or 113.04 cm2. [Use π = 
or 3.14]
Video Examples: Area of a Circle
Solved Example on Area of a Circle
Ques:
Find the area of a circle, if the diameter of the circle is 4 cm. [Use π = 3.14]
Choices:
A. 25.12 cm2
B. 6.28 cm2
C. 12.46 cm2
D. 12.56 cm2
Correct Answer: D
Solution:
Step 1: Let r be radius of the circle.
Step 2: Diameter of the circle = 2r
Step 3: 4 = 2 × r.
Step 4: r = 4/2 = 2 cm
Step 5: Area of the circle = π × r 2 [Formula.]
Step 6: Area of the circle = 3.14 × 4 = 12.56 [Substitute the values of π and r.]
Step 7: So, the area of the circle is 12.56 cm2
Quick Summary
- Area is the space within a circle's boundary.
- Area is calculated using the formula A = πr², where r is the radius.
- π (Pi) is approximately 3.14.
🍎 Teacher Insights
Emphasize the difference between radius and diameter. Use visual aids to demonstrate the concept of area. Provide plenty of practice problems with varying levels of difficulty.🎓 Prerequisites
- Basic Algebra
- Understanding of Pi
- Concept of Radius and Diameter
Check Your Knowledge
Q1: What is the area of a circle with a radius of 5 cm? (Use π = 3.14)
Q2: A circle has a diameter of 10 inches. What is its area? (Use π = 3.14)
Frequently Asked Questions
Q: What is the value of Pi?
A: Pi (π) is a mathematical constant approximately equal to 3.14159.
Q: How do I find the radius if I know the diameter?
A: The radius is half of the diameter (r = d/2).
Q: What are the units for area?
A: Area is measured in square units, such as cm², m², in², ft².