Two angles of a triangle measure 25° and 75 °. What is the measure for the third angle?
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The sum of the angles of a triangle is of 180 degrees.
Let the third angle be x.
25 + 75 + x = 180
We'll isolate x to the left side moving the rest of the numbers to the right:
x = 180 - 100
x = 80
Therefore, the third angle measures 80 degrees.
Since we know the sum of the angles of a triangle must be 180, we can determine the third angle by subtractng the two angles that you have from 180.
x = 180 - 75 - 25
x = 80
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