Example Find the equation of a circle with radius 3 units and centre (0, 0) The radius, r = 3 and r 2 = 9, so the equation of the circle is x 2 + y 2 = 9 ...

How do you find the area of a circle? Can you measure the area of a circle and use that to find a value for Pi?

National Pi Day is held each year on March 14. It honors 3.14 the ratio of the circumference of a circle. You can also get deals on food too.