Find the value of $m$ if the points $(5, 1), (2, 3)$ and $(8, 2m )$ are collinear.

The area of the triangle whose co-ordinates are $(2012, 7), (2014, 7)$ and $(2014, a)$ is $1 \,sq$ unit. The sum of possible values of $a$ is

If the area of a triangle formed by the points (k, 2k) (-2, 6) and (3, 1) is 20 square units. Find the value of k.

$(3, 1), (-3, 2)$ and $\displaystyle (0,2-\sqrt{3})$ are the vertices of __________ triangle of area ___________.