PI
Definition Of Pi
The ratio of the circumference of a circle to its diameter is known as "Pi".
More About Pi
The 16th letter of the Greek alphabet.
It is symbolically represented as π.
The value of pi is 
or approximately equal to 3.14159.
Pi is an irrational number.
Examples of Pi
According to the definition, Pi = Circumference/Diameter which is shown in the figure i.e. π = C/d, where C is the circumference of the circle and d is its diameter.
Video Examples: What is the Meaning of Pi
Solved Example on Pi
Ques: Find the circumference of the circle.
Choices:
A. 14π cm
B. 16π cm
C. 18π cm
D. 20π cm
Correct Answer: C
Solution:
Step 1: Circumference is the distance around a circle.
Step 2: Circumference of a circle = diameter × π. [Formula.]
Step 3: = 18 × π [Substitute the value.]
Step 4: = 18π [Multiply.]
Step 5: So, the circumference of the circle is 18π cm.
Quick Summary
- Pi is approximately equal to 3.14159.
- Pi is an irrational number.
- Pi is used to calculate the circumference and area of circles.
🍎 Teacher Insights
Use physical objects like circular lids and string to demonstrate the relationship between circumference and diameter. Emphasize that 3.14 is an approximation.🎓 Prerequisites
- Circles
- Diameter
- Circumference
- Ratio
Check Your Knowledge
Q1: What does π represent?
Q2: A circle has a diameter of 6cm. What is its approximate circumference?
Frequently Asked Questions
Q: What is the symbol for Pi?
A: The symbol for pi is π, which is the 16th letter of the Greek alphabet.
Q: Is Pi a rational or irrational number?
A: Pi is an irrational number, meaning it cannot be expressed as a simple fraction and its decimal representation goes on infinitely without repeating.