Answer:
Angle A = 55°
Step-by-step explanation:
So a property of an isosceles triangle is that two of the sides are equal, and that the angles opposite to those sides are also equal. What the problem wants you to know here is that angle A and angle C are equal.
Knowing that, we can set up the following system of equations and solve:
3x + 40 = x + 50
2x = 10
x = 5
So now that we know x = 5, we can plug that into angle A:
angle A = 3(5) + 40
= 15 + 40
= 55
