Answer:
[tex] \boxed{b\degree = 36\degree} [/tex]
Step-by-step explanation:
Property used: An exterior angle of a triangle is equal to the sum of the opposite interior angles.
[tex] = > 81 \degree + b \degree = 117 \degree \\ \\ = > b \degree = 117 \degree - 81 \degree \\ \\ = > b \degree = 36 \degree [/tex]
