81 - 8^2 is 17 ..............
Answer:
A = 125º
Step-by-step explanation:
Missing angle is the supplement of 157.5
180 - 157.5 = 22.5
----------------------------
Sum of angles in triangle is 180
22.5 + (-10x) + (-x + 20) = 180
Combine like terms
-11x + 42.5 = 180
Subtract 42.5 from both sides
-11x = 137.5
Divide both sides by -11
x = -12.5
---------------------------
A = -10(-12.5)
A = 125º
You can prove the proofs by showing your work to prove the proofs.
