C because first you would find the circumference of the circle which is pi times diameter, which is 18.84 but since it is a semi-circle you would divide by 2 which is 9.42. Then you do 3+3=6 + the length which is 6 so you get 12. 12+9.42=21.42 and if you round that to the nearest tenth it is 21.42.
I attached an image with the complete question.
Answer:volume of attic = 1526.04 ft³
Explanation:Volume of cone can be calculated using the following rule:
Volume =

* area of base * height
Volume =

* π * radius² * height
We are given that:
π = 3.14
radius = 18/2 = 9 ft
height = 18 ft
Substitute in the equation to get the volume as follows:
Volume =

* 3.14 * (9)^2 * (18) = 1526.04 ft³
Hope this helps :)
We will because we will turn into aliens and then shoot dogs into the universe
Here, you would complete it with the Pythagorean Theorem.
So, A^2 + B^2 = C^2
So 14^2 + B^2 = 14^2
This equals = B = 11.49