I just read an example of vectors in my book which is confusing me.
Three particles A,B and C are at the vertices of an equilateral trinagle ABC. Each of the particle moves with constant speed v. A always has its velocity along AB, B along BC and C along CA. They meet each other at the centroid. At any instant, the component of velocity of B along BA is $v\cos60^\circ$.
I don't understand how the particles meet at the centroid and why the component of velocity of B along BA is $v\cos 60^\circ$.