Answer:
1) 20 degrees. 2)60 degrees. 3)30 degrees
Step-by-step explanation:
For number 1, there are 180 degrees in a triangle. Since we already know all the measures, we can just make an equation.
90+31+3x-1=180
120+3x=180
-120 -120
3x=60
x=20
for number 2, the traingle must be equilateral because they all have the same measure. That's why it's 60 because 60*3=180
Last one:
Same as 1st one. Make an equation: x+3x+2x=180
Combine like terms
6x=180
x=30
