Answer:
140°
Step-by-step explanation:
Every triangles angles when combined equals 180°
In an isosceles triangle there are 2 acute angles and one obtuse angles.
It was given that the base angle/acute angle is 20°
This brings us to our equation. 20° + 20° + x = 180°
20 + 20 = 40
40 + x = 180
Now we solve algebraically:
180-40= 140
Therefore the answer is x = 140°
I hope this helps!