The answer can't be C or D because the unit of volume is always cubed. The formula for volume of cylinder is (pi)(r^2)(h) . The pi(r^2) part is the formula for area of a circle which is what the base of the cylinder is. Fortunately the area is already given as 28.2. Plug that into the volume formula and plug in 3.1 for the height and multiply. I get 87.42 and the answer choice B seems to be the closest option
Answer:
Check the explanation
Step-by-step explanation:
Kindly check the attached images below to see the step by step explanation to the question above.
Answer:
Option B. 
Step-by-step explanation:
we know that
The volume of a cone is equal to

Solve for the radius r
That means-----> isolate the variable r
Multiply by 3 both sides

Divide by
both sides

square root both sides

Answer:
(D) is the right answer
Step-by-step explanation:
The cross section will be a quadrilateral when the intersecting plane forms a closed four sided polygon along with the pyramid.
A triangular pyramid has four faces. So, to form four straight lines and therefore a quadrilateral, the intersecting plane must intersect all four faces.
A. In this case the plane will only intersect one side of the pyramid so four sided polygon can't be formed.
B. It will only intersect the two sides of the pyramid but the cross section will not be a quadrilateral.
C. In this case the plane will intersect three sides of the pyramid so the cross section will be a triangle not a quadrilateral.
D. In this case the plane intersects all the four faces forming a closed polygon of 4 straight lines so the cross section will be a quadrilateral.
So, the Correct Option is (D) : When the plane intersects the base and all three lateral faces of the pyramid, the cross section of the triangular pyramid will be a quadrilateral.