In a circle the Greek letter π is used to represent the ratio of ________.

Explanation:

Pi (π):

• The number π ("pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159.

​Circumference of the circle = 2 × π × r = π × d

Where r = radius of the circle, d = diameter of the circle

• The number π appears in many formulae across mathematics and physics.
• It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although fractions such as 22/7 are commonly used to approximate it.
• Consequently, its decimal representation never ends, nor enters a permanently repeating pattern.
• It is a transcendental number, meaning that it cannot be a solution of an equation involving only sums, products, powers, and integers.