Lines b and c
they both go up 2 and over 1 (rise over run is slope)
The measure of the third angle is 50 because a triangle has a sum of 180 degrees by angle.
so... 46+84=130 and to get to 180, the last angle has to be worth 50.
Https://mathbitsnotebook.com/Algebra1/RealNumbers/RNProp.html