A cylindrical metal pipe has a diameter of 20 millimeters and a height of 21 millimeters. A cylindrical hole cut out of the center has a radius of 6 millimeters. A cylinder is shown. A smaller cylinder is cut out of the middle of the larger cylinder. Both have a height of 21 millimeters. The diameter of the larger cylinder is 20 millimeters, and the the radius of the smaller cylinder is 6 millimeters. Which expressions represent the volume of metal needed, in cubic millimeters, to make the pipe? Select two options. 21π(10)2 – 21π(6)2 π(20)2(21) – π(6)2 2,100π – 756π 7,644π 1,344