834 cubic centimeters. First, determine the cross section of the pipe. And that's simply the area of the outer diameter minus the area of the inner diameter. So calculate the inner and outer radius of the pipe IR = 2.6 / 2 = 1.3 OR = 2.8 / 2 = 1.4 Now the inner and outer areas. IA = pi * IR^2 = 3.14159265 * 1.3^2 = 5.309292 OA = pi * OR^2 = 3.14159265 * 1.4^2 = 6.157522 Cross section area is simply the outer area minus the inner area. So CS = 6.157522 - 5.309292 = 0.84823 Now figure out the volume in cubic inches by multiplying the cross section by the length. Be sure to include the 12 to convert from feet to inches. V = 0.84823 * 5 * 12 = 50.8938 Now to convert from cubic inches to cubic centimeters. Since there is 2.54 centimeters per inch, just multiple by 2.54^3 to convert. 50.8938 * 2.54^3 = 50.8938 * 16.38706 = 834