Answer:
16.96 degree
Step-by-step explanation: Step 1 redraw and label a b c your triangle
Step 2 trig function given any 2 or 3 sides use cos = cos x = adj/hyp = cos-1 (3.5/12) = 73.04 then 90- 73.04 = 16.96 degree Bonus fact of the day ! we can also remember when given any 2 angles in problem solving then use sin angle * angle 73.04 * 16.96 = 16.92 for the base side measure then sin 73.04 * 16.92 or 12 * sin 16.96 degrees = 3.5 side
