Math questions dealing with 'Pi'?

Question

The number of inches in the perimeter of an equilateral triangle equals the number of square inches in the area of its circumscribed circle. what is the radius, in inches, of the circle?

thanks, =)

Answer 1

Let R be the radius. Then the area of the circumscribed circle is pi*R^2 in^2. The perimeter of the triangle is pi*R^2 in inches. Thus, each side is (pi/3)*R^2 inches long. You can draw 3 radii from the apexes of the triangle to the center. You can extend one of the radii to an opposite side. You form a 30/60/90 triangle with the extension of the radii from the center, half of one side, and the radii as hypotenuse. So these lengths are in the ratio 1/sqrt(3)/2, respectively.
Then R/2 = (pi/6)*R^2/sqrt(3). Then R=(1/pi)3sqrt(3).

Answer 2

well im in 7th grade but i only know what pi equals, but i havent learned that yet. try it out or ask your parents for help or maybe even your teacher. or you can just find out what the diameter is and cut it in half and you have your radius!

srry that is all ive got. i hope this helped.
:)