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
yes
Triangles and rectangles.
there are more than 1 because there are more than 1 triangles on geomotry
No, because angels don't come to earth for triangles. However, you can certainly have right angled equilateral triangles.
triangles and straight lines you can get on decomposing a rectangle.