Angular position for 2nd order diffraction

[Bolter]

Homework Statement

See image attached below

Relevant Equations

dsin(theta) = m*lambda

Here is my problem

I have given this a go and get 26.77 degrees as my angular position

My concern is do I double this angle to get the angular width between both 2nd order maxima's (which would be 53.53 degrees) or do I just leave it as 26.77 degrees?

Thanks for any help!

 

[TSny]

Looks good. I believe they are asking for the angle between the central max and either of the 2nd order maxima.