Based on the popular textbook by A.P. Ershova and V.V. Goloborodko, page 167 typically contains problems from Self-study Work S-13 (or the end of S-12), which focuses on the properties of Central and Inscribed Angles in a circle.
According to the theorem on inscribed angles, an inscribed angle is equal to half of the central angle that subtends the same arc. geometriia kniga ershovoi str 167 variant a2 8 klass
∠ABC=12⋅∠AOCangle cap A cap B cap C equals one-half center dot angle cap A cap O cap C Based on the popular textbook by A