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"What is the area of the smallest square mirror that can be used to 'hide' a cylinder with a radius of 1 unit and height of 2 units in a corner of the cubic room?"

This is the question. It said that the mirror has one side / edge on the floor and two corners on the walls (one each). What should I read on to decide which orientation(s) would yield the right answer? Or is this the kind of question where we have to try all the possibilities and pick one that matches the requirements?

Edit : 'Hide' is not hiding from view. It only wants the smallest square area (the way it should stand as mentioned) contained in the last face of a triangular pyramid that's capable of containing the cylinder.

Yaya Manisya
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  • Depends on what you mean by "hide" and "square". If you want that the mirror completely close off view of the cylinder from outside the mirror, then it needs to leave no holes, not even from above, as a point right at the edge of that hole can see everything behind it. But if the mirror must be rectangular, then the only choice is to go all the way to the roof. And if the mirror must be square, that means its distance across must be the same as the height, which means the mirror is the same size as the sidewall of the cube. So it depends on how big the cube is. – Paul Sinclair Jun 28 '21 at 15:45
  • I thought the 'hide' already made it distinct from the usual hide (this was specifically noted originally, but I thought it's unnecessary since I'm not seeking the numerical answer here). I guess it only wants the smallest square area (the way it should stand as mentioned) contained in the last face of a triangular pyramid that's capable of containing the cylinder? I'll edit the problem. – Yaya Manisya Jun 28 '21 at 21:41
  • Maybe you should just reprint the actual statement of the problem, as your edit is not clear at all. – Paul Sinclair Jun 28 '21 at 23:30
  • This is my own question so reprint is impossible. The cylinder must be confined within a tetrahedral space with 3 perpendicular faces (of the walls) and a triangular fourth face that circumscribed a square mirror. We want to know the minimum size of that mirror, but how you oriented the cylinder within it will change the shape of the tetrahedron, and ultimately the size of that mirror. It is easy, just seeing if others see it like I did. Delete this away, as usual. – Yaya Manisya Aug 14 '23 at 23:27

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