Answer:
B = 18
Step-by-step explanation:
The exterior angle is equal to the sum of the opposite interior angles
D = B+C
117 = 8x+27 + B
Angle A and angle B are supplementary, which means they from a straight line. They add to 180 degrees
<A + <B = 180
18x + <B = 180
Solving for B
B = 180 -18x
Putting this into the above equation
117 = 8x+27 + 180-18x
Combing like terms
117 = 207-10x
Subtract 207 from each side
117-207 = 207-207 -10x
-90 = -10x
Divide by -10
-90/-10 = -10x/-10
9= x
We need to find angle B
B = 180 -18x
= 180 - 18(9)
= 180 -162
= 18
