Answer:
55
Step-by-step explanation:
m angle A and m angle C are equal sine two of those sides are equal. You would do 3x + 40 = x +50
You subtract x, leaving it to be 2x + 40 = 50
Subtract the 40, leaving it be 2x = 10
Divide both sides by 2, which leaves x = 5
and then you would do 3(5) + 40, which is 55
