trig
posted by Anonymous .
A security camera needs to be set so that the angle of view includes the area from a doorway to the edge of a parking lot.The doorway is 16m from the camera. the edge of the parking lot is 24m for the camera. the doorway is 28m from the edge of the parking lot. what angle of view is needed for the camera

My sketch is a triangle with sides 16, 24 and 28 , and I am looking for the angle Ø opposite the 28
by cosine law
28^2 = 16^2+24^2  2(16)(24)cosØ
768cosØ = 48
cosØ = 48/76
Ø = 50.8°