Use Pythagoras theorem

Two triangles are similar

(6+3)*12/2 - 6*8 /2 = 30
9*724 answer is 6516. . . . . . . . .
Radius is half of diameter.
Circumference can be found using the equation C=2(pi)r or C=(pi)d.
r=radius, d=diameter
(pi) is about 3.14 or 22/7
Answer:
x=139
Step-by-step explanation:
angles on a straight line add up to 180 degrees