Because any triangle's three angles add up to 180°, all you have to do is add the other two angles together and subtract that sum from 180.
180 - (124 + 33) = 23°
Hope this helps,
♥<em>A.W.E.</em><u><em>S.W.A.N.</em></u>♥
(P.S. You can give <em>5accsdeletedalready</em> Brainliest, you need either 2 people to be able to <em>choose</em><em> </em>Brainliest or you have to wait until the next day.)