A certain Circle of paper has x degrees cut out of it. The two cut edges are taped together, curling the paper up into a right circular cylinder of height 8 and with a base of radius 6. What is the value of x?

Question

A) 74
B) 90
C) 120
D )144
E) 200

Answer 1

The slant height of the cone is the original radius of the paper circle.

So, r = 10

The new circumference of the base is .6 of that, so 40% of the circle was lost. 40% of 360° is 144°.