Explanation:
Interior angle sum of a triangle is 180°
therefore 180=5x-30+x+10+6x-40, simplifying like terms gives us
180=12x-60, solving for x leaves us with x=20.
angle 1 = 5x-30 = 100-30=70
angle 2 = x+10 = 20+10=30
angle 3 = 6x-40 = 120-40=80
In conclusion the smallest angle has a measure of 30°