from a donkey
The study of trigons - or triangles.
They are triangles all of whose sides are of the same length.
Pyramid
Triangles with three equal sides are called equilateral triangles.
tri as in 3 angles as in the ends . He's right but i wil explain more. Equilateral triangles get there name from all sides being equal hence the name equilateral. Right triangles get there name from having a right angle, or ninety degree angle. I don't know about iscoceles.
isoceles, equilateral, and scalene...
equilateral and scalene
Triangles and rectangles.
yes
No, because angels don't come to earth for triangles. However, you can certainly have right angled equilateral triangles.
there are more than 1 because there are more than 1 triangles on geomotry
triangles and straight lines you can get on decomposing a rectangle.