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).
A radian is a unit of angular measure. A turn in a full circle has an angle of 2Ï radians. A radian is a unit of measuring angles. It is shown by the symbol rad or, less often, c (for circular measure). The radian was once an SI unit, but was done away with in 1995. A milliradian is 1/1000 of a radian.