triangle counting - type 3

Let cos A+cos B+cos C=(3)/(2) in a triangle then the type of the triangle is

Do the points joining L(6,4), M(-5,-3) and N(-6,8) from a triangle ? Mention the type of triangle so formed .

Introduction to Permutation & Combination | Fundamental Principle of Counting | Types of Events

If the circumcentre of a triangle lies outside the triangle, then what type of triangle is it ?