bonanova 77 Report post Posted February 25, 2014 Here is a piece of plywood in the shape of an isosceles triangle. The side lengths are 1, 1, sqrt(2) units. Quick and dirty representation: A | \ | \ | \ | \ B--------------C The angle at B is a right angle. We'd like to cut this into two pieces of equal area. There are many ways to do this with a single cut. Which cut has the shortest distance? 1 1 Share this post Link to post Share on other sites

0 superprismatic 11 Report post Posted February 27, 2014 a circular arc, with center at either (1,0) or (0,1), of length .25×sqrt(2)×sqrt(pi) which is approximately 0.62666. The radius is sqrt(2)/sqrt(pi). Share this post Link to post Share on other sites

0 TimeSpaceLightForce 11 Report post Posted February 26, 2014 Share this post Link to post Share on other sites

0 bonanova 77 Report post Posted February 27, 2014 halves.JPG With a careful reading of the OP can you do slightly better? Share this post Link to post Share on other sites

0 bonanova 77 Report post Posted February 27, 2014 Kudos to both TSLF and SP. Share this post Link to post Share on other sites

0 superprismatic 11 Report post Posted February 27, 2014 @Bonanova or anyone else who may have an interest in this: Do you have a proof that that circular arc is the shortest? Conceivably, a piece of a trigonometric curve, or exponential curve, or another conic section may be shorter. The possibilities are endless. Share this post Link to post Share on other sites

0 bonanova 77 Report post Posted February 27, 2014 @Bonanova or anyone else who may have an interest in this: Do you have a proof that that circular arc is the shortest? Conceivably, a piece of a trigonometric curve, or exponential curve, or another conic section may be shorter. The possibilities are endless. Yes, it's called the isoperimetric problem, generally stated, what is the curve of constant length that encloses the greatest area? Equivalently, what shape of constant area has the smallest perimeter? The answer is a circle. A 45^{o} arc can be reflected 7 times into a full circle. Symmetry demands this answer, although rigorous proofs abound. Here is a general discussion. In three dimensions (think soap bubble) a sphere encloses more volume than any other closed surface of the same area. isoperimetric = iso (same) perimetric (perimeter). Share this post Link to post Share on other sites

Here is a piece of plywood in the shape of an isosceles triangle.

The side lengths are 1, 1, sqrt(2) units.

Quick and dirty representation:

A| \

| \

| \

| \

B--------------CThe angle at

Bis a right angle.We'd like to cut this into two pieces of equal area.

There are many ways to do this with a single cut.

Which cut has the shortest distance?

## Share this post

## Link to post

## Share on other sites