Note that two opposite sides are parallel and other two, are not parallel, but are congruent. We can conclude that quadrilateral is isosceles trapezoid. Recall that if a quadrilateral is an isosceles trapezoid, then its diagonals are congruent. Therefore, by the definition of congruent sides, their measures are equal.
JL= KM
We are given KP= 4 and PM= 7. Note that KM= KP+ PM. Therefore JL= KP+ PM.