Help me in michelson interferometer

[kelambumlm]

Homework Statement

Find the angular radius of the tenth bright fringe in a Michelson interferometer
when the central-path difference (2d) is (i) 1.50 mm and (ii) 1.5 cm.
Assume the orange light of a krypton arc is used and that the interference is
adjusted in each case so that the first bright fringe forms a maximum at the
centre of the pattern.

Homework Equations

2d sin theta = m lambda or
2d cos theta= m lamda

The Attempt at a Solution

i confuse to use the equation.

theta= cos-1 or sin -1 (6057 armstrong x 10th) divide 1.50mm
the answer that i get is not logic.

 

[Redbelly98]

I'm unaware of circular fringes being produced in a Michelson interferometer. Ideally, there either is or isn't light at the detector or screen.

Is there any more information given in the problem statement?