This app displays a central angle and an inscribed angle and their angle measures. You can move the points along the circle and see that the Inscribed angle is ALWAYS half of the Central Angle (which is equal to the intercepted arc).

This app displays a central angle and an inscribed angle and their angle measures. You can move the points along the circle and see that the Inscribed angle is ALWAYS half of the Central Angle (which is equal to the intercepted arc).[br]As you adjust the points B, C, and D, record the measures of the Inscribed Angle and the Central Angle, as well as the ratio of the Inscribed Angle to the Central Angle.