Monochromatic light of wavelength = 620 nm from a distant source passes through a slit 0.450 mm

Monochromatic light of wavelength λ = 620 nm from a distant source passes through a slit 0.450 mm wide. The diffraction pattern is observed on a screen 3.00 m from the slit. In terms of the intensity 10 at the peak of the central maximum, what is the intensity of the light at the screen the following distances from th center of the central maximum?
(a) 1.00 mm;
(b) 3.00 mm;
(c) 5.00mm?