Stuck in wave interference question

[toesockshoe]

Homework Statement

Light of 576 nm wavelength is directed at a two-slit apparatus and produces a famous intensity pattern on a screen 75.0 cm away. Each slit is 0.434 mm wide, and the center-to-center separation of the slits is 0.640 mm.

Given that the intensity at the very center of the pattern is 5.00×10−4W/m2 , determine the intensity at a point a distance 0.900 mm , measured along the screen, from the very center.

The question had lots of numbers, so I just posted a pic instead of typing everything in latex. (sorry!)


2. Homework Equations
Look at picture!

The Attempt at a Solution

Look at picture in attachment!

 

[blue_leaf77]

The $d$ in the intensity pattern equation is the center-to-center distance between the slits, it's not the distance between the inner edges of the slit as you seem to have assumed.