In the given question endpoints of the line (Hypotenuse) have been given and we have to find the length of the hypotenuse.
Distance between the two points
and
is given by the expression,
Distance =

Distance between two points (7, 8) and (-1, -1) will be,
Distance =

=

=

And the right triangle with the hypotenuse formed by the line joining two points (7, 8) and (-1, -1) will be as given in the figure attached.