An observer (o) is located 900 feet from a building (b). the observer notices a helicopter (h) flying at a 49° angle of elevation from his line of sight. how high is the helicopter flying over the building?

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .

Were is the diagram?