Consider that there are m collinear points out of total n points in a plane. To construct a triangle we require 3 non-collinear points. Hence, the number of triangles will be ‌nC3−‌mC3. Since, all the point in the above question are non-collinear, hence n=10 and m=0 Therefore, the total number of triangles are =‌10C3 =‌