Some symbols I sent on my mobile phone can't be written, so I can only say them in words. Please look at the quantity! Solution: The surface area of machine parts can be regarded as the lateral area of a cylinder plus the surface area of a prism, because the lateral area of a cylinder is S1= 2RL = 2x3x25 =150 = 471(square millimeter). The surface area of prism S2 = 12x5x6+2x6x (half 1) x 12x 12x (half root number 3) is about = 1 108.25 (square millimeter), so Then the surface area of 10000 parts is15792500mm2 =15.7925m2, so the required weight of zinc is15.7925x0.1=/kloc-0. ! !