Using the concept of inner angle capacities, the maximum angle measurement that can exist inside this triangle would be 180 degrees. This means that the missing angle within the triangle would be 180 - (40 + 75), or 65 degrees.
Now, knowing that the angle we are looking for is a supplementary angle to the one we just calculated, we can find it’s angle measurement by subtracting the one we know from 180 degrees, since it’s a straight line. This means that the angle measurement of this outside angle would be equal to 180 - 65, or 115 degrees.
