Answer:
70
Step-by-step explanation:
Hello There!
In order to find the measure of angle B we need to solve for x
Remember the sum of the angles in a triangle is 180
so we can solve for x using the equation
180=40+x+20+2x-30
step 1 combine like terms
40+20=60 60-30=30
2x+x=3x
now we have
180=3x+30
step 2 subtract 30 from each side
180-30=150
30-30 cancels out
step 3 divide each side by 3
150/3=50
3x/3=x
we're left with
x=50
Now we plug in 50 into x in 2x-30
2*50=100
100-30=70 so we can conclude that
angle B = 70
