The distance between the points $A(-3, 4)$ and $O(0, 0)$ is $OA = \dots$

Find the points on the $X$-axis at a distance of $13$ from the point $(11, 12)$.

If $A(2, 9)$,$B(-2, 1)$,and $C(6, 3)$ are vertices of a triangle and the area of $\Delta ABC$ is $28$,find the length of the altitude drawn from $A$ to the side $\overline{BC}$.

The distance of point $P(2, -3)$ from the $X$-axis is $\ldots \ldots \ldots \ldots .$.

The point which lies on the perpendicular bisector of the line segment joining the points $A (-2,-5)$ and $B (2,5)$ is

Using the distance formula,show that $(4, 3)$,$(5, 1)$,and $(1, 9)$ are collinear.