Central angle

Match the angle to the required region: use the smaller central angle for a minor arc or sector and $360^\circ-\theta$ for the corresponding major one.

For an arc, use the central angle belonging to the required arc. If the diagram gives the other angle, calculate $360^\circ-\theta$ first.

For a sector, use the central angle belonging to the requested region. If the smaller angle is given but the major sector is required, calculate $360^\circ-\theta$ first.