HI PLEASE HELP 16 POINTS
(will give brainliest for actual answer)

Drivers of semitrucks and other large vehicles pay close attention to signs similar to the one below. These signs indicate a change in the grade or slope of the road. Look at the black scalene triangle in the sign.
1. How can the third-angle theorem be applied to find all three angle measurements in the black triangle?
2. Are the black triangles above congruent or similar? Explain.

(image below)