what is the measure of ∠b?\n98°\n108°\n118°\n128°

Explanation:

Step1: Recall sum - of - interior - angles formula

The sum of interior angles of an $n$-sided polygon is given by $(n - 2)\times180^{\circ}$. For a hexagon ($n = 6$), the sum is $(6 - 2)\times180^{\circ}=720^{\circ}$.

Step2: Set up an equation

Let $\angle B=x$. Then $x + 170^{\circ}+90^{\circ}+117^{\circ}+102^{\circ}+133^{\circ}=720^{\circ}$.

Step3: Simplify the left - hand side

$x+(170 + 90+117 + 102+133)^{\circ}=720^{\circ}$. $x + 612^{\circ}=720^{\circ}$.

Step4: Solve for $x$

$x=720^{\circ}-612^{\circ}=108^{\circ}$.

Answer:

$108^{\circ}$