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.