GUATEMALA CITY - Torrential rains brought by the first tropical storm of the 2010 season pounded Central America and southern Mexico, triggering deadly landslides. The death toll stood at 15 Sunday but authorities said the number could rise.
Archimedes proved the formula for the area of a circle (A = Ï r 2, where r is the radius of the circle) and showed that the value of Ï lay between 3 + 1/7 (approximately 3.1429) and 3 + 10/71 (approximately 3.1408).
The circle is such a common shape that we take it for granted ... but there is more to it that just a common shape. Mathematically, the circle is defined as the set of all points that are the same distance from a given point, called the center. That distance is called the radius. The word radius comes from the Latin word for rod or spoke of a wheel, and the radii, or spokes, radiate out from the center.