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This post pulls together Are two convex solids with all corresponding shadows equal in area congruent? and What can be said about 2 convex solids with corresponding maximal planar sections having equal area? and could be of interest if the answers to the questions raised in both those posts are negative.

  • Let there be two convex solids P and Q that hover over the XY plane satisying: areas of shadows of both P and Q on the XY plane are equal and areas of maximal area cross sections of both P and Q that are parallel to XY plane are also equal. Now, if the same rotations are done on both P and Q keeping their centers of mass fixed and both areas areas of shadow and max cross section) of P remain equal to the corresponding areas of Q for any same rotation done to both P and Q, what can one conclude about P and Q - will they be congruent/have equal volume/equal surface area?

  • Same question as above with 'perimeter' replacing 'area'.

  • If congruence cannot be guaranteed in either case above, will both equality of areas and equality of perimeters holding be sufficient?

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