[1] First, remember that the sum of the angles in a triangle must add up to 180.
[2] We are told two of the angles, 44 and 66, but we are missing the third.
[3] Combining [1] and [2], we know that 44 + 66 + ? = 180. In other words,
110 + ? = 180
so,
? = 70*
The missing angle 3 is equal to 70 degrees.