How many triangles?
Line has 6 points on it and has five points lying on it. if and are parallel to each other, then how many triangles can we get from these 11 points?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
The way to look at the problem is by asking "in how many ways can i choose one point from the first line and two points from the second line" that goes for both sides. So choosing one point from 'l' and two points from 'm' have 6C1×5C2 =6x10= 60 ways. And choosing two points from 'l' and one from 'm' have 6C2x5C1 = 15x5=75 ways. Over all we have 60+75 = 135 ways to choose the points of the triangle. Therefore we have 135 different triangles from both lines.