A triangles interior angles sum is always 180°. So we need to find B. To do that we will add the angles we have, then subtract to find angle B:-
43 + 66 = 109
180 - 109 = 71
Check:-
43 + 66 + 71 = 180
SO, angle B is 71°.
Hope I helped ya!!!!!!!!!!!!☺☺☺
