The Triforce in Zelda games!
4 congruent pairs
Absolutely. Any two congruent right triangles will form a rectangle, and if the right triangles are isosceles right triangles, they will form a square.
triangle based pyramid
An hexagon is made up out of 4 triangles
yes
4 congruent pairs
Isosceles Tetrahedron.
Absolutely. Any two congruent right triangles will form a rectangle, and if the right triangles are isosceles right triangles, they will form a square.
An equilateral triangular pyramid
triangle based pyramid
A square
An hexagon is made up out of 4 triangles
yes
4
No. For example the triangles with sides {3, 4, 5} and {6, 8, 10} are similar but not congruent.
A REGULAR SQUARE PYRAMID.
An isosceles trapezoid can be subdivided into 4 right angle triangles.