One angle of a quadrilateral is 111° and the remaining three angles are equal. Find three angles.

Sum of all four angles = 360° 
One angle = 111° 
Let measure of other three angles = x (They are equal)
111° + 3x = 360° 
3x = 360° - 111° 
3x = 249
x = 249/3 
x = 83

Therefore, all the other angles of the quadrilateral measure 83° each.
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