D. 16.8 units
A radius is half of the diameter, so to get the answer all you need to do is multiply the length of the given radius by 2.
8.4x2= 16.8
X=32
All triangles add up to 180 degrees so if the right angle is 90 degrees then you have 90 degrees left. Next, you take the 2x and x-6 and plug them into the equation 3x-6=90. Once you solve that you get x=32.
Answer:
301.59
Step-by-step explanation:
your answer was almost right you just forgot to multiply by 9