Calculating Slit Width Using Microwave Wavelength

[Funf]

Homework Statement
Microwaves of wavelength 2.80 cm fall on a slit and the central maximum at a distance of 1.0 m from the slit is found to have a half-width (i. e. distance from middle of central maximum to first minimum) of 0.67 m. Find the width of the slit.

 

[Alter Baron]

Have you tried the problem yet?
Hint: Half width is half the distance between two maxima.