Is the line through points P(2,-9) and Q(6, -13) perpendicular to the line through points R(5,-1) and S(1,-5)?

Two lines are perpendicular if their slopes are in a relation .

So we need to find slopes and if the above relation holds then we can claim the lines are perpendicular.

To find slopes, use slope formula

The first slope of a line passing through is

The second slope of a line passing through is

Now check if is true

This means the two lines are perpendicular.

Hope this helps.

no, because the sides are not congruent