pvris-svlk

OM = ON (Equal chords are always equidistant from the centre)
          OE = OE (Common)
          ∠OME = ∠ONE (perpendiculars)
          So, ΔOEM ≅ ΔOEN (by RHS similarity criterion)
          Hence, ∠MEO = ∠NEO (by CPCT rule)
          ∴ ∠BEQ = ∠CEQ