1. The problem statement, all variables and given/known data Three points are located at the vertices of an equilateral triangle whose sides equals a. They all start moving simultaneously with velocity v constant in modulus, with the first point heading continually for the second, the second for the third, and the third for the first. How soon will the points converge? 2. Relevant equations 3. The attempt at a solution I suppose this one is an easy problem, but i am still not sure if i did it the correct way. I found the original distance of a point from the centroid (where the points converge) which is a/√3 and the component of velocity along the line joining the centroid and a point is vcos(30°), therefore time taken by the points to converge is vcos(30°)/(a/√3)=2a/3v. This matches the answer given in the answer key but i don't understand why this method works here? What if it was not an equilateral triangle? Any explanation on this would help. Thanks!