If r = 7 units and x = 8 units, then what is the volume of the cylinder shown above?
A.
210 cubic units
B.
56 cubic units
C.
1,568 cubic units
D.
392 cubic units

If r 7 units and x 8 units then what is the volume of the cylinder shown above A 210 cubic units B 56 cubic units C 1568 cubic units D 392 cubic units class=

Respuesta :

AL2006

Strange as it may seem, NONE of the choices on the list
is the volume of that cylinder,

The volume of any cylinder is    (π) (radius)² (height).

We know all of these numbers.  We only need to pour them into
the hopper on top of the volume machine, and turn the crank.

                                (π)      x  (radius)²  x (height)

                          =  (3.14...) x (7 units)² x (8 units)

                          =  (3.14...) x (49 units² x 8 units)

                          =  (3.14...) x (392 units³)  =  1,231.5... units³

I don't see that number among the choices, or anything close to it.

Choice-D is interesting.  As we saw during our calculation,
392 is  (radius)² x (height).  But that's not the volume, because
it hasn't been multiplied by  π  yet.