a rectangle
a square...
Yes. They can form a kite.
parallelograms
Yes it can. Every equilateral triangle is an acute one. To put it another way, the family of acute triangles includes all equilateral ones.
can two triangles put together make a square
Three triangles.
a rectangle
three triangles, and 1 square+2 triangles
if you put 3 triangles together you get a bigger triangle.
a square...
yes a square
A square already has 2 right angle triangles within it
Four triangles, similar to the large one, but one third the size.
4 rectangles / Correction: two triangles.
Yes. They can form a kite.
Sliding them together makes a Big Triangle, flipping them makes a Diamond.