1. The problem statement, all variables and given/known data For a sphere of radius r, find the solid angle Ω in steradians defined by spherical angles of: a.) 0°≤θ≤ 20°, 0°≤ø≤360°; 2. Relevant equations dA = r2 sin dθ dø (m2) dΩ = dA / r2 = sin dθ dø (sr) 3. The attempt at a solution I think I understand what a steradian (sr) is, on a sphere, and I need to find what ratio of a 4∏ is formed by the above limits, but I can't make the connection on how to form that ratio. ?