A ring's a right cylinder of radius r1 w/ a cylindrical hole of radius r2. Ring's height=h Find surfacearea+vol

cylindrical-radius

#1

A ring’s a right cylinder of radius r1 w/ a cylindrical hole of radius r2. Ring’s height=h Find surface area+vol. r1=12m r2=6m h=8m. Write form. w/ r1,r2,h that’ll find SA+V for any ring where 0<r2<r1

Answer:

I believe this is stating that there is an outside cylinder with an
inner core that has been removed. To find the SA of this
outside cylinder, you not only find the SA of that cylinder, but add
the inner core’s SA, which can be found by finding the lateral
SA of the inner cylinder. Then subtract the SA of both top and
bottom circles of that inner cylinder.

You add the lateral surface of inner core’s cylinder SA
because it is the ‘inside’ core of the larger cylinder

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