So you have a circle. What is the area of that circle? Surely everyone remembers that the area of a circle is: Where Pi (π) is of course the number and r is the radius of the circle. Where does this ...

Evan O’Dorney leaps from his seat and snatches the chalk from his teacher’s hand. “I think it goes like this,” the eighth-grader exclaims. He has come up with a formula for the number of ways to ...

Arc length is a fraction of circumference. Area of a sector is a fractions of the area of a circle. Both can be calculated using the angle at the centre and the diameter or radius. Practice circle ...

The shortest distance between two points is a straight line. This is one of the basic principles of Euclidean geometry. But we live on a spherical Earth, so we cannot travel the straight line path ...

Three mathematicians show, for the first time, how to form a square with the same area as a circle by cutting them into interchangeable pieces that can be visualized. Around 450 BCE, Anaxagoras of ...