Question

Find the ratio in which the line segment joining the points (2, 4,5) and (3, −5, 4) is divided by the yz-plane.

Answer 1

Let the yz - plane divide the line sgement joining the points (2, 4,5) and (3, −5, 4) in m : 1.
Now, we know that on yz-plane the coordinate of x is 0.
$$\begin{gathered} \therefore \frac{m\times 3+1\times 2}{m+1}=0 \\ \Rightarrow 3m+2=0 \\ \Rightarrow m=-\frac{2}{3} \end{gathered}$$
Hence, yz - plane divide the line sgement joining the points (2, 4,5) and (3, −5, 4) in 2 : 3 externally.