Answer:
55
Explanation:
The base angles of an isosceles triangle have the same measure
3x+40 = x+50
Subtract x from each side
3x+40-x = x+50-x
2x+40 = 50
Subtract 40 from each side
2x+40-40 = 50-40
2x = 10
Divide each side by 2
2x/2 = 10/2
x = 5
We want angle A
3x+40
3*5 +40
15+40
55