Question

if three angles A,B and C of a triangle are in AP then angleB=?
plz elaborate your answer

Answer 1

let angle B=a°
and as the are in AP, let the common difference = d
so angle A = a-d
& angle C= a+d
here 1st term is (a-d) & common difference is d
but angle A+B+C= 180°
so (a-d) + a + (a+d)=180°
a-d+a+a+d=180
3a=180°
a=180/3=60°
Thus angle B = 60°