Используя данные, представленные на рисунке, найди ∠MKN.

The central angle ∠MOK subtends the arc MK. The inscribed angle ∠MKN subtends the same arc MK. The measure of an inscribed angle is half the measure of its intercepted arc (or half the measure of the central angle that subtends the same arc). Therefore, ∠MKN = ∠MOK / 2. Given that ∠MOK = 140°, then ∠MKN = 140° / 2 = 70°.