Andrew Lentvorski wrote:
Ralph Shumaker wrote:
Apparently, the two pyramids in question are *not* the same, except
that they are both completely equilateral. One has a square base.
The other has a triangle base. The answer seems like it would be 7
since the one has 5 sides, the other has 4 sides, and one side of
each is completely covered up. But 7 is *not* the correct answer.
Can you guess what it is? (BTW, the official SAT answer apparrently
*was* "7", but was challenged, and found to be wrong.)
The trick has to do with the dihedral angles:
Tetrahedron = 70.53
Octahedron = 109.47 (if you split it in half it's the second pyramid)
109.47+70.53 = 180.00
-a
... which gives you how many sides left exposed? (Bonus points: Name
the shapes of each side and the number of each shape (somebody other
than Andrew :-) since he apparrently has it).)
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