Phase Difference Problem, Ratio of I/Io

[Lemmy]

Homework Statement

What is the ratio of the intensity at this point to the intensity at the center of a bright bridge

Homework Equations

GIVEN:
Wavelength=6.9x10^-7m
d=0.00014m (distance between slits)
L=12m (Length to screen/point)
Y=14mm

EQUATION:
I=Io cos^2(phi/2) [(Sin (B/2))/(B/2)]
I/Io=cos^2(phi/2) [(Sin (B/2))/(B/2)]

The Attempt at a Solution

I have phi, solved for b/2 and plugged it in and did everything.

I STILL GOT IT WRONG??! is my equation wrong??

 

[quantumdude]

Where is "this point" and what's a "bright bridge"?