Find the distance between the following pairs of points: $(a, b)$ and $(-a, -b)$.

Find the coordinates of the points which divide the line segment joining $A (-2, 2)$ and $B (2, 8)$ into four equal parts.

Find the coordinates of a point $A,$ where $AB$ is the diameter of a circle whose centre is $(2,-3)$ and $B$ is $(1,4).$

Find the area of a triangle whose vertices are $(1, -1), (-4, 6)$ and $(-3, -5)$ (in square units).

Let $A(4, 2)$,$B(6, 5)$,and $C(1, 4)$ be the vertices of $\Delta ABC$. Find the coordinates of points $Q$ and $R$ on medians $BE$ and $CF$ respectively such that $BQ : QE = 2 : 1$ and $CR : RF = 2 : 1$.

The two opposite vertices of a square are $(-1, 2)$ and $(3, 2)$. Find the coordinates of the other two vertices.