It seems like your message may be incomplete. If you’re looking for the measure of angle \( a \), and you've provided the value “153”, I assume you might want to know how to relate this to angle \( a \) or something else.
If you were provided that \( a = 153^\circ \), then the measure of angle \( a \) is simply \( 153^\circ \).
However, if you need assistance with a specific problem involving angle \( a \) or if it’s part of a geometric figure, please provide additional details so I can assist you accurately!