Competition problem — Geometry — Maths Olympiad Prep

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Geometry Difficulty 4.7 AIME Find the answer

7. (Wuhu City) In a square $ABCD$ with side length 2, $E$ is the midpoint of $AB$ . Now fold along $EC$ and $ED$ so that $AE$ and $BE$ coincide, and points $A$ and $B$ coincide, named as point $O$ . Then the volume of the tetrahedron $O-CDE$ is:

Pick one

Solution

$\mathrm{C}$

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Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.