Mhanifa please help! Look at the picture attached!!!

Answer:
(17)
Sum of interior angles of a quadrilateral is 360°
(18)
Sum of interior angles of a hexagon is 180°*(6 - 2) = 720°
(19)
Interior angles of a given pentagon are all marked as congruent, so the exterior angles are congruent too.
Sum of exterior angles is 360°.