Therefore the slant height is 10 + 15 = 25 12 x Find the slant height. Find the radii of each circle. Find the volume of the frustum. 10 8 1. Find x and add it to 10. Two ~triangles = 20x = 12x+120 8x = 120 x = 15 Therefore the slant height is 10 + 15 = 25

2. Find the radii. Draw the triangles inside both cones. 15 12 25 20 Small cone Large cone Since we have 3, 4, 5 triangles, the radius of the small cone is 9 and the radius of the larger cone is 15.

The volume of the frustum is equal to the volume of the large cone minus the volume of the smaller cone. V = π r2h - π r2h V = π 152(25) - π (9)2(15) V = 1875 π - 1215 π V = 660 π

Find the volume of this pyramid if its base is 12, width 9, height 15 Volume of a pyramid: V = bwh w b Find the volume of this pyramid if its base is 12, width 9, height 15 V = 540

12.6 Volume of Spheres V = π r3