Answer:
b° = 100
Step-by-step explanation:
A triangle always adds up to 180° in its interior angles;
To calculate the angle missing in the triangle with 55° and 45°
; 180° - (55° + 45°)
; 180° - 100°
; The angle is 80°
Then for us to calculate the angle at b°
A straight line makes an angle of 180°
;Hence the angle b°
;180° - 80°
Therefore.... b° = 100°
