Question
The line segment joining A $(4, 7)$ and B $(-6, -2)$ is intercepted by the y – axis at the point K. write down the abscissa of the point K. hence, find the ratio in which K divides AB. Also, find the co-ordinates of the point K.

Answer

Since, point K lies on y-axis, its abscissa is $0.$
Let the point K $(0, y)$ divides AB in the ratio $k : 1$
We have,
$x=\frac{k \times(-6)+1 \times 4}{k+1} $
$ 0=\frac{-6 k+4}{k+1} $
$ k=\frac{4}{6}=\frac{2}{3}$
Thus, K divides AB in the ratio $2: 3.$
Also, we have:
$y=\frac{k \times(-2)+1 \times 7}{k+1} $
$y=\frac{-2 k+7}{k+1}$
$ y=\frac{-2 \times \frac{2}{3}+7}{\frac{2}{3}+1}$
$ y=\frac{-4+21}{2+3} $
$y=\frac{17}{5}$
Thus, the co-ordinates of the point K are $\left(0, \frac{17}{5}\right)$

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