Answer:
25°
Step-by-step explanation:
See attached for reference.
Recall that all interior angles of a triangle sum up to 180 deg
in this case we are given the values of of the interior angles 57 deg and 98 deg.
Let the 3rd angle be x
Hence,
57° + 98° + x° = 180°
155 + x = 180 (subtract 155 from both sides)
x = 180 - 155
x = 25°
