Impossible Constructions?

Date: 04/08/97 at 22:14:35
From: Josh Steffenson
Subject: Impossible Constructions

My geometry teacher told us there were 3 impossible problems/
constructions, one of which is trisecting an angle. 

What are the other two? 

Thanks,
Josh Steffenson

Date: 04/09/97 at 11:45:16
From: Doctor Wilkinson
Subject: Re: Impossible Constructions

The other two are

 (2) Duplicating the cube: given the side of a cube, construct
     the side of a cube with twice the volume

 (3) Squaring the circle: given the radius of a circle,
     construct the side of a square with the same area as the
     circle with the given radius.

-Doctor Wilkinson,  The Math Forum
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