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 area of a circle is pi times the square of the length of the radius, or pi r squared: The modern symbol for pi [ ] was first used in our modern sense in 1706 by William Jones, who wrote: Pi (rather than some other Greek letter like Alpha or Omega) was chosen as the letter to represent the number 3.141592...