For inscribed angles, the measure of the inscribed angle is equal to half of the measure of the intercepted arc. This means that m∠R = 1/2(NQ); 23 = 1/2(NQ)
Multiply both sides by 2: 46 = NQ
The measure of the central angle is equal to the measure of the intercepted arc; m∠O = NQ; m∠O = 46