Since these are all right triangles, you can use sin, cos, and tan functions to find angles.
19. arcsin (39/44)
20. arcsin (26/33)
21. arccos (24/36)
22. arccos (20/23)
23. arctan (10/33)
24. arctan (13/16)
Please know that if you need numerical values for these answers, make sure your calculator is in degrees and not radians. Also note that “arc” is equivalent to the inverse of trig functions.