Find the ratio in which the line ax + by + c = 0 divides the line segment joining p(x1,y1) and Q (x2,y2).
You are given t = (ax2+by2+c)ax1+by1+c
The ratio is mn=(ax1+by1+c)ax2+by2+c,which is −1t.
We can derive this formula in the following way.
First assume the ratio is K:1. Let the point of intersection be R. We can find the co-ordinates of R interms of K. We know R lies on the other line also. Substitute the co-ordinates in the given line to find the value of K.
We can use this approach while solving problems. It is good to remember the formula as well.