Brain Teasers
Hole in One
Fred took a ball that has a 13 inch diameter and drilled a circular hole through the center of it. The hole was 5 inches wide, but how deep is it?
Answer
12 inches.To solve this one, we can use the work of Pythagoras. If we draw the ball and hole from the side, they look like a circle with a rectangle in it, with all four points of the rectangle touching the circle.
We know the length of the short side and we need the length of the long side. To get it, we'll need the length of the diagonal of the rectangle to create a triangle. By looking back at our drawing, we can see that the diagonal of the rectangle is equal to the diameter of the ball.
From that we have a triangle where hypotenuse, c, is 13 inches, leg a is 5 inches, and we want to solve for leg b. Using c^2=a^2 + b^2, we solve for b and find that the depth of the hole is 12 inches.
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Comments
Very Good Job!Good One
hmm... simple math... but math never killed anyone, now did it? it was easy, (well, very easy actually ), but good enough to keep me in shape!
ah, what am i talking about here? of course i loved it! i love math! go math! go math!
ah, what am i talking about here? of course i loved it! i love math! go math! go math!
Although I really don't like math much, I enjoyed this teaser.
i didn't get it but y would anyone want to drill a hole in a ball and how can someone drill a hole in the dead center. that one was hard
Cool, I knew that I liked this site because it reminded me how to do all this crazy math stuff!
Excellent workout,thanks for the tease.
Oh. Ha, I said 6.5 inches, to go through the center point, not thinking about drilling out an axis.
Oh. Ha, I said 6.5 inches, to go through the center point, not thinking about drilling out an axis.
Excellent teaser - very enjoyable!
The old 5 - 12 - 13 rightangle triangle, eh?
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