圆心角: angle at centerangle at the centrecenter anglecentral anglecentre angleradius angle
圆周角: angle at the circumferenceangle in a circular segmentangle in circular segmentangle of circumferenceangle of cirumferencecircumferential angleinscribed angleround angle
倍: Ⅰ名词(跟原数相同的量) times 短语和例子五倍 five times; 百倍 hundredfold; 该厂产量成倍增长。 the output of the factory has doubled and redoubled. 十是五的两倍。 ten is twice as much as five.Ⅱ形容词(加倍) double; twice as much 短语