Question: 189. The inside dimensions of a rectangular wooden box\nare 2 inches by 4 inches by 6 inches. A cylindrical\ncanister is to be placed inside the box so that it stands\nupright when the closed box rests on one of its six\nfaces. Of all such canisters that could be used, what is\nthe radius, in inches, of the one that has maximum\nvolume?\nOptions:\n(A)  2\n(B)  4\n(C)  5\n(D)  6\n(E)  8 Random thoughts:
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Since the radius is squared, the biggest volume cylinder will have the biggest possible radius. To achieve that, let the smaller dimension of the rectangular box be the height. So, it will have 6x4 width x length. The biggest cylinder must fit both dimensions, so it must have at most a diameter of 4, so the radius will be 2. The final answer: (A).
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