Determine if the sequence is arithmetic or geometric, write the explicit equation and then find the given term. 1. 11th term: 5, 3, 1,-1, ...
2. 23rd term: 0.1,0.15, 0.2, 0.25, ...
3. 6th term: 25, 75, 225, 675, ...
4. 22nd term:-2, -5, -8, -11, -14,
5. 10th term: a = 320, r = 0.5
6. 50th term: -9.2, 13. 24. 35.

For every corresponding pair of cross sections, the area of the cross section of a sphere with radius r is equal to the area of the cross section of a cylinder with radius and height 2r minus the volume of two cones, each with a radius and height of r. a cross section of the sphere is and a cross section of the cylinder minus the cones, taken parallel to the base of cylinder, is the volume of the cylinder with radius r and height 2r is and the volume of each cone with radius r and height r is 1/3 pie r^3. so the volume of the cylinder minus the two cones is therefore, the volume of the cylinder is 4/3pie r^3 by cavalieri's principle. (fill in options are: r/2- r- 2r- an annulus- a circle -1/3pier^3- 2/3pier^3- 4/3pier^3- 5/3pier^3- 2pier^3- 4pier^3)