Question

Calculate the distance between $A(5,-3)$ and B on the Y-axis whose ordinate is $9$.

Answer 1

We know
Any point on y-axis has coordinates of the form $(0,y)$
According to the question
Ordinate of point $B=9$
Since, $B$ lies on y-axis so its coordinates are $(0,9)$
$AB=\sqrt{{(0-5)}^2+{(9+3)}^2}=\sqrt{25+144}=\sqrt{169}=13units$