Question

The diameter if a closed cylinder is 21 cm and height is 10 cm find the total surface area of the cylinder

Answer 1

given,
radius=21/2,
height=10.
then,we know that,
t.s.a=2πr(r+h)
=2×22/7×21/2×(21/2+10)
=66×41/2
=33×41
=1353cm2

Answer 2

d=2r
r=d/2=21cm/2
TSA of cylinder=2πr(h+r)
$2 \times \frac{22}{7} \times \frac{21}{2} (10 + \frac{21}{2} ) \\ 2 \times \frac{22}{7} \times \frac{21}{2} \times \frac{41}{2 } = {1353cm}^{2}$