Your supervisor asks you to measure the index of refraction of a piece of plastic. You notice that, because of scattering of the light, you can see the path of a laser beam through the plastic. You decide to shoot a laser beam toward the plastic at several different incident angles and measure the refraction angle in the plastic. Your data are as follows:

Incident angle..............................Refraction angle

15°..........................................................9°

30°..........................................................19°

45°..........................................................26°

60°..........................................................34°

75°..........................................................37°

Use the best-fit line of an appropriate graph to determine the plastic’s index of refraction.