The radius of a circle or a sphere is the distance between the center and the edge. The radius can be used to calculate a circle's diameter, area and circumference. Likewise, a sphere's volume is ...

The circumference of a circle is the distance around the circle. It is another name for the perimeter of a circle. The circumference of a circle is calculated using the formulae: \(\text{circumference ...

The dimensions of the Earth was first measured by Greek philosopher Eratosthnes in 200 B.C. by using simple geometric methods. He dug a narrow well at Syene (now Aswan). The well would reflect the ...