Ponder This Challenge - February 2026 - Blot-avoiding backgammon strategy
- Ponder This
Ponder This Challenge:
This month's puzzle is from Denis Boris.
Let ABC be a primitive right triangle with integer sides and integer area. ("Primitive" means that the sides are relatively prime.)
Let DEF be an isosceles triangle with integer sides.
Suppose ABC and DEF have the same perimeter, and the same area.
Part 1
Find the lengths of the sides of ABC and of DEF.
Part 2
Prove your solution is unique.
(We do not know the solution to Part 2.)
We will post the names of those who submit a correct, original solution! If you don't want your name posted then please include such a statement in your submission!
We invite visitors to our website to submit an elegant solution. Send your submission to the ponder@il.ibm.com.
If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com
Part 1 Solution
ABC has sides 135, 352, 377;
DEF has sides 132, 366, 366.
The common perimeter is 864, and the common area 23760.
Part 2 Solution, provided by Dan Dima [PDF]
If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com