Reflex ∠MOR = 2 × 124° = 248° (angle at the centre is twice the angle at the circumference) ∠MOR = 360° - 248° = 112° (sum of angle at a point is 360°) ∠OMN = 360° - (124°+ 48° + 112°) (sum of angles in a quadrilateral is 360°) = 360° - 284° ∴ ∠OMN = 76°