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 normal area of a circle is A=Ïr2. Since a semicircle is just half of a circle, the area of a semicircle is shown through the formula A=Ïr22. We can solve for r to show an expression for the radius of a semicircle when given the area: A=Ïr22. 2A=Ïr2. 2AÏ=r2. r=â2AÏ. If given the diameter: The diameter, like in a normal circle, is just twice the radius.