Respuesta :

CoastsideDad
a=140
b= 20

The 70° angle creates a 140 degree arc. Inscribed angles equal 1/2 of arc created.
The central angle (a) is equal to the arc.
So, angle ‘a’ = 140.
The triangle is isosceles, so the base angles are equal.
180-140=40
40/2 = 20