Three angles of a quadrilateral are $21^\circ$, $ 66^\circ$, and $134^\circ$. How many degrees are in the measure of the fourth angle?
<|im_start|>system
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<|im_start|>user
Three angles of a quadrilateral are $21^\circ$, $ 66^\circ$, and $134^\circ$. How many degrees are in the measure of the fourth angle?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
139^\circ
Three angles of a quadrilateral are $21^\circ$, $ 66^\circ$, and $134^\circ$. How many degrees are in the measure of the fourth angle?
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