puzzles! ii

ok, as promised, here are the answers to yesterday's the puzzles! i post. don't read on if you still want to figure them out yourself!

circle puzzle (that i found at halfway there):


click pic to source
the picture for the circle puzzle contains some extra information you don't need... i.e. the 3". to find the radius, all you have to do is flip the diagonal in the rectangle so that its ends are located at the center and the circumference of the circle... and voila! you've got your radius, which is 8".

if you need to see a picture, click here.

match puzzle:



like our friend brutalgourmet mentioned in his comment on the same post, nobody said that the solution had to be 2-dimensional. make a triangle with 3 matches on a table, then connect each of the remaining 3 matches to its corners, and lift them up to meet at an apex in the air -- and you have yourself a tetrahedron.

if you need to see it, i've posted a little youtube clip here.

giggle... snicker...