In the given figure, $A, B, C$ and $D$ are four points, and no three points are collinear. $AC$ and $BD$ intersect at $O$. There are eight triangles that you can observe. Name all the triangles.

Explain the term: Triangle
 

Explain the term: Parts or elements of a triangle 

Explain the term: Scalene triangle
 

Explain the term: Equilateral triangle
 

Explain the term: Acute triangle
 

Explain the term: Right triangle