Can you please explain , what do incentre , orthocentre and centroid mean?
orthocentre-The three altitudes intersect in a single point, called the orthocenter of the triangle. The orthocenter lies inside the triangle (and consequently the feet of the altitudes all fall on the triangle) if and only if the triangle is not obtuse (i.e. does not have an angle greater than a right angle).
centroid-a plane figure or two-dimensional shape X is the intersection of all straight lines that divide X into two parts of equal moment about the line. In physics, the word centroid may mean the geometric center of the object's shape, as above; or its physical center of mass or the center of gravity, depending on the context.
Hope it is clear now.