# 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