Finding Internal Volumes and Total Surface Areas of a Cylinder
A Pencil case in the shape of a cylinder with a hemisphere at each end has a diameter of 8cm and a total length of 22cm.
(i) Find the internal volume of the pencil case, correct to one decimal place.
(ii) Find the Total surface area of the pencil case, correct to the nearest cm².
What I did for this, I don't think Im right so its more where did I go wrong (if at all).
(i) (pi)(r²)(h) + 2 times the hemisphere 2/3(pi)(r³)
My final answer using this method gave me 971.3cm³
(ii) 2(pi)(r)(h) + 2(pi)(r²) = 452.16 (This was for the TSA of the cylinder)
Now for the hemisphere
I did 3(pi)(r)² X 2 which gave me 301.44.
I said 301.44 + 452.16 = 753.6cm²