How Far is the Third-Order Bright Fringe from the Central Maximum?

[noobie!]

Homework Statement

Monochromatic light passes through 2 narrow slits 0.25mm apart and forms an interference pattern on screen 1.5m away.If light with a wavelength of 680nm is used,what is the distance between center of central maximum and center of the third-order bright fringes?

Homework Equations

sorry don't have..

The Attempt at a Solution

d=0.25mm ,y=1.5m lambda=680x10^-9, central max=0, third order=3
i tried using sin@=m x lambda /d ,but y is given..i think i should have use it but then i don't know where n when to use..can you please hint me?

 

[noobie!]

sorry,i've done it already,im so sorry..