All triangles have a sum degree measure of 180.
We know ∠B, which is 39.8.
∠A is known as well, the little box at the corner indicates a right angle, which means it has a degree of 90.
To find ∠C, we can construct a formula to find the unknown value.
1. 180 = ∠A + ∠B + ∠C Isolate ∠C.
2. 180 - ∠A - ∠B = ∠C
3. 180 - 90 - 39.8 = ∠C
4. 50.2 = ∠C
Therefore, angle C is 50.2 degrees. The other information is written to throw you off.