1. The problem statement, all variables and given/known data given that sin theta = 3/5, 0 < theta < pi/2 find sin theta/2 2. Relevant equations http://www.intmath.com/Analytic-trigonometry/sinalphaon2.gif [Broken] 3. The attempt at a solution I appologize that I don't know how to use all the symbols on a keyboard (square roots, etc) But I have so far gotten it to : square root of 1-3/5 all over 2. I have a sample of this same problem in my book, but they don't explain the next step. Suddenly this problem from here just turns into square root of 1/5...can someone please explain how they got to there? Thank you all.