If the diameter is 8 what is the cirumference?

Answer 1

remember that the diameter is the distance across the plane of a circle that passes through the center point of a circle. The radius is half this distance. The circumference of a circle (the distance around the outside) is determined by the arc length 's'. 's' equals the square of the radius times the angle of the circle, in this case 360 degrees. We havr to convert 360 degrees to radians to do the math and that equals 2 times Pi.

this sound complicated but it's not. The equation works out to be

Circumference = 2 x (radius squared) x Pi

or

C = 2 x (16) x Pi

C = 32 x Pi

use your calculator for pi or multiply 32 by 3.14