Answer :
In a triangle ABC.
a+b+c=180 .
AB=BC and angle B=80
let angle a and c be x because AB=BC.
a+b+c=180
x+x+80=180
2x+80=180
2x=180-80
2x=100
x=100÷2
x=50
angle A=50
a+b+c=180 .
AB=BC and angle B=80
let angle a and c be x because AB=BC.
a+b+c=180
x+x+80=180
2x+80=180
2x=180-80
2x=100
x=100÷2
x=50
angle A=50