Answer: x = 40
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Work Shown:
A+B+C = 180 ..... three angles of any triangle add to 180
(2x+10)+(x)+(2x-30) = 180
5x-20 = 180
5x = 180+20 .... adding 20 to both sides
5x = 200
x = 200/5 ... dividing both sides by 5
x = 40
This is the measure of angle B
We can stop here.
If you need to know the values of the other angles, then,
- angle A = 2x+10 = 2*40+10 = 90
- angle C = 2x-30 = 2*40-30 = 50
Then note how A+B+C = 90+40+50 = 90+90 = 180 which helps confirm our answer.