The perpendicular distance of the point $(-3, 8)$ from the $Y$-axis is........

Show that $(10, -18), (3, 6)$ and $(-5, 2)$ are the vertices of an isosceles triangle.

If the vertices of $\Delta PQR$ are $P(3, 10)$,$Q(6, 5)$,and $R(1, 2)$,then $\Delta PQR$ is a $\dots$ triangle.

$A$ person begins his journey from point $A$. From $A$,he moves $800 \, m$ towards north to reach point $B$. From $B$,he moves $500 \, m$ towards east to reach point $C$. From $C$,he moves $400 \, m$ towards north to reach point $D$. Find the direct distance in $m$ from $A$ to $D$.

Find $k$ if $(1, 7), (2, 4)$ and $(k, 5)$ form a right triangle.

Find the circumcentre of the triangle with vertices $(4,6), (5,1),$ and $(4,0)$.