Please help? =(

You perform a double-slit experiment in order to measure the wavelength of the new laser that you received for your birthday. You set your slit spacing at 1.13 mm and place your screen 9.03 m from the slits. Then, you illuminate the slits with your new toy and nd on the screen that the tenth bright fringe is 4.74 cm away from the central bright fringe (counted as the zeroth bright fringe). What is your laser's wavelength 1 expressed in nanometers? am In a double-slit interference experiment, the wavelength is A = 697 nm, the slit separation is d = 0.180 mm, and the screen is D = 32.0 cm away from the slits. What is the linear distance Ax between the seventh order maximum and the third order maximum on the screen? m_m Structures on a bird feather act like a diffraction grating having 7000 lines per centimeter. What is the angle of the first-order maximum for 477 nm light shone through a feather? angle