dna86
Offline
Upload & Sell: Off
|
Here is something that might be interesting to you - or maybe not.
I recently purchased a new reflector and lots of ads say that they fold to 1/3 the original size. This seemed strange to me - that somehow it should be a lot smaller, so I started thinking mathematically. Try to follow along:
Suppose we have a reflector that is 3ft in diameter when popped out. A 3 ft reflector will have pi*d circumference, which is about 9.42 ft. The area is pi*r^2, which is about 7.065 sq. ft.
When you fold the 3 ft reflector, the rim will go around 3 times making the new circle haev a circumference that is 1/3 the unfolded size, so that makes about 3.14 ft. Working the formula for circumference backwards, means that the diameter will be 1 ft. This is interesting, because the diameter is 1/3 the original size. However, the area of this circle is .785 sq ft, which is exactly 1/9 the area of the folded out size.
So, the next time someone tries to tell you that your reflector takes up 1/3 the amount of area when folded, you can confidently tell them that it's really 1/9, which is pretty neat when you think about it - folding reflectors is pretty efficient.
Ok, I know this is probably totally useless, but there it is!
|
