Helli, Wilmer!
A Pythagorean right triangle has integer sides and area. Everybody knows that!
For each of these, two integer-sided isosceles triangles with integer area exist.
Example: two 3-4-5 right triangles can be used to make isosceles triangles
. . 5-5-6 and 5-5-8.
Is there any reasons why this is not "widely known/quoted"?
Maybe because it is "too obvious"?
. . (Is there such a thing?)
An integer-sided isosceles triangle (with an even base and integral altitude)
. . can be bisected into two congruent Pythagorean triangles.
Code:
*
|
*|*
|
* | *
|
* | *
|
* * * * *
These, in turn, can be assembled into another integer-sided isosceles triangle.
Code:
*
* | *
* | *
* * * * * * *