Answer:
3: D) 11
4: D) 12
7: C) 63
8: A) Adjacent Angles
Step-by-step explanation:
Let's pretend the sides of a triangle are A B and C.
The third side of a triangle is always greater tham A-B and lesser than A+B. This is called the triangle inequality theorem.
For 7 and 8, we have three lines that come together at one point (adjacent angles), and the vertical angle postulate where two mirrored angles will always have the same angle.