Look at Fig. 2.34. Mark (a) a point A which is in the interior of both ∠1 and ∠2; (b) a point B which is in the interior of only ∠1; (c) a point C in the interior of ∠1. Now state whether points B and C lie in the interior of ∠2 also.

One possible marking (as in the figure): A lies inside both ∠1 and ∠2; B lies inside only ∠1; C lies inside ∠1.
Thus, B is not in ∠2; C is not in ∠2.
Follow these simple checks.
Note: If a point lies on an arm, it is not counted as interior.