A shape formed by joining any 3 non-collinear points is a triangle.
non-collinear means NOT IN THE SAME LINE.
take any three points on paper which are non collinear n join you will get a triangle
 it is seen that since we take 3 points there are 3 corners to the's shape is like this :
1 5 1
Triangle has three Angles
triangle is formed by joing any 3 non-collinear points.
it has 3 corners
" Δ " it will be like this
1 5 1