1. Find the position of the centroid of the shaded area http://imgur.com/ieiSPPY 2. The black triangle with the square cut out is where the centroid must be located.I know that the object is symmetrical and the triangle can be divided into parts with two smaller right angled triangles I have having immense difficultly studying centroids because my book does not explain how to equate them properly. 3. I understand that the centroid of a triangle is where the medians intersect I believe the formula is the sum of the sides divided by the amount of sides ,I just do not know how to calculate the centroid of the shape once you remove the area of the square.I am uncertain about where I should place my reference point . I would appreciate any help/links/resources with understanding centers of gravity and centroids ,I am a new student of physics and I am very keen to learn. thank you.