Using the acoustic peak to measure cosmological parameters
  Recent measurements of the cosmic microwave background radiation by the Boomerang experiment indicate that the universe is spatially flat. Here some simple back-of-the-envelope calculations are used to explain their result. The main result is a simple formula for the angular scale of the acoustic peak in terms of the standard cosmological parameters: l=193*[1+3(1-Omega_0)/5+(1-h)/5+Omega_Lambda/35]. 
Neil J. Cornish