Question

PLEASE HELP.....
1.) do the coordinates J(2, 2), K(-1, 3), L(-2, -1) form a right triangle?
2.) Given quadrilateral RSTU, tell which sides (if any) are parallel and which are perpendicular for the coordinates of the vertices.

R(-l, 1), S(l, -2), T(4, 0), U(3, 3)
3. The coordinates G(7, 3), H(9, 0), I(5, -1) form a right triangle (true or false)