Question 34493
It looks like you will have the right distance when you take the square root of 100.
For the distance between P(-4, 3) and Q(2, -5):
{{{d = sqrt((x2-x1)^2 + (y2-y1)^2)}}}
{{{d = sqrt((2-(-4))^2 + (-5-3)^2)}}}
{{{d = sqrt(6^2 + (-8)^2)}}}
{{{d = sqrt(36 + 64)}}}
{{{d = sqrt(100)}}}
{{{d = 10}}}

For the coordinates (x, y) of the midpoint of PQ:
{{{x = (x1+x2)/2}}} and {{{y = (y1+y2)/2}}}
{{{x = (-4+2)/2}}} and {{{y = (3-5)/2}}}
{{{x = (-2)/2}}} and {{{y = (-2)/2}}}
{{{x = -1}}} and {{{y = -1}}}

The coordinates of the midpoint are: (-1, -1)