A quadrilateral I believe.
Answer:
339.12 cubic millimeters
Step-by-step explanation:
The picture of the question in the attached figure
we know that
The volume of the figure is equal to the volume of the two hemispheres (one sphere) plus the volume of the cylinder
so
step 1
Find the volume of the cylinder
The volume is given by

where
B is the area of the base of cylinder
h is the height of cylinder
we have

we have

----> the radius is half the diameter


substitute

step 2
Find the volume of the sphere
The volume is given by

we have
----> the radius is half the diameter
substitute

step 3
Adds the volumes

8.40/3 = £2.80 each
...............
13 is 141. A octagon has 1080 degrees and if you add all the angles up you get 939 and 1080-930=141