If two angles of a triangle are $75°$ each, find the third angle.

Find the angles of a triangle in which the biggest angle is double the smallest angle, and the third angle is half of the sum of the other two angles. 

Find the value of $x$.

Find the value of $x$.

Find the value of $x$. 

Find the value of $x$.

Which of the following sets of three angles can be that of the angles of a triangle?

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