laser diffraction problems?

Question

4. You measure a distance from diffraction to screen to be 285[mm]. What should be the angle to the first spot measured off axis, if the distance from the center spot is 1.204E+02[mm]?
angle = __________________ [degree]
Use three significant figures or N/A, if not enough information is given.


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5. What is the previous answer in radian?
angle = _____________[radian]
Use three significant figures or N/A, if not enough information is given.

PLEASE HELP AND EXPLAIN STEP BY STEP THANKS, HAVING A HARD TIME!!

Answer 1

It's not absolutely clear, but it looks as though you are being asked for the angle formed by something 120.4 mm sideways at a distance of 285 mm.

This gives Tan (angle) = 120.4/285 (= a bit less than 0.5)

So work that out, then press the tan^-1 button, sometimes labelled arctan, and the answer will come out.

For radians, either do the calculation again setting the calculator to radians, or multiply the degrees by (pi/180). pi = 3.1415926...