+0

# cut a circle in half not through middle

+3
252
6

cut a circle in half not through middle

Guest Oct 26, 2014

#4
+81045
+13

We can also cut a circle with radius R in half by removing a circular area with a radius = R/√2 from within the circle...

To prove this, we have

pi*R^2 - pi*r^2 = (1/2)*pi*R^2   ......where r is the radius we're looking for........so.......

(1/2)pi*R^2 = pi*r^2   divide both sides by pi

(1/2)R^2 = r^2   take the positive root of both sides

r = (1/√2)R = R/√2

Note that......as long as the circular area removed lies totally witin the circle, it doesn't have to be concentric with the larger circle!!!

CPhill  Oct 26, 2014
Sort:

#1
+5

I don't understand what you are trying to say.

Guest Oct 26, 2014
#2
+17711
+8

If you don't use a straight line, there will be an infinite number of ways to divide a circle into two parts, where each part has the same area as the other.

The yin-yang picture is one.

geno3141  Oct 26, 2014
#3
+3

are you trying to say there are $${\mathtt{\infty}} = \infty$$ possibilities to make a circle into $${\frac{{\mathtt{1}}}{{\mathtt{2}}}}$$? oh, i knew that. :)

-Robert

Guest Oct 26, 2014
#4
+81045
+13

We can also cut a circle with radius R in half by removing a circular area with a radius = R/√2 from within the circle...

To prove this, we have

pi*R^2 - pi*r^2 = (1/2)*pi*R^2   ......where r is the radius we're looking for........so.......

(1/2)pi*R^2 = pi*r^2   divide both sides by pi

(1/2)R^2 = r^2   take the positive root of both sides

r = (1/√2)R = R/√2

Note that......as long as the circular area removed lies totally witin the circle, it doesn't have to be concentric with the larger circle!!!

CPhill  Oct 26, 2014
#5
+91469
+5

I really like Gino's and Chris's logic.  Thanks guys

Melody  Oct 27, 2014
#6
+81045
+5

Geno had logic out the ying-yang....me???....I was just throwing something against the wall and hoping that some part of it would stick !!!!

CPhill  Oct 27, 2014

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