In addition to our Pi Digits learning tool, we propose several simple tools using Pi:
Circle calculator: calculate the radius, the perimeter, the circumference and the area of a circle from any of these four values.
Sphere calculator: calculate the radius, the perimeter, the area and the volume of a sphere from any of these four values.
Distance on a sphere calculator: use this tool to calculate the distance between two points on a sphere. You can use it for example to calculate the distance between two towns on Earth.