Let there be angles a b c
a+b+c=180°
let a be 130
b+c=50°
ln the triangle formed by bisectors
1/2c+1/2b+d=180
since
b+c=50°
therefore
1/2c+1/2b=50/2°
1/2c+1/2b=25°
therefore
1/2c+1/2b+d=180
since
1/2c+1/2b=25°
therefore
d=155°
d is the angle between bisectors