When you plot the three points on the graph it makes a triangle. As it rotates around the x axis, the points at 2,0 and 2,-2 make a circle, which becomes the base of the cone.
To work out the Circumference of a circle, we must o the calculation πd π x d If we fill in the information we know π x 10.4 3.14 x 10.4 (to 2 d.p.) ↓ 32.656 (units)
