Question

The lateral surface area and the total surface area of a cylinder with base radius 7 m and height 9 m are
respectively
a) 396 m², 704 m² b) 704 m. 396 m² c) 396 m, 704 m
d) 704 m. 396 m​

Answer 1

Given :

• Radius of Cylinder = 7m
• Height of Cylinder = 9m

To Find :

• C.S.A of Cylinder.
• T.S.A of Cylinder.

Solution :

$\longmapsto\tt{Radius=7m}$

$\longmapsto\tt{Height=9m}$

Using Formula :

$\longmapsto\tt\boxed{C.S.A\:of\:Cylinder=2\pi{rh}}$

Putting Values :

$\longmapsto\tt{2\times\dfrac{22}{\cancel{7}}\times{\cancel{7}}\times{9}}$

$\longmapsto\tt{44\times{9}}$

$\longmapsto\tt\bold{396{m}^{2}}$

So , The C.S.A of Cylinder is 396m²...

_______________________

Using Formula :

$\longmapsto\tt\boxed{T.S.A\:of\:Cylinder=2\pi{r(r+h)}}$

Putting Values :

$\longmapsto\tt{2\times\dfrac{22}{\cancel{7}}\times{\cancel{7}}(7+9)}$

$\longmapsto\tt{44(16)}$

$\longmapsto\tt\bold{704{m}^{2}}$

So , The T.S.A of Cylinder is 704m²...

Option a) 396m² , 704m² is correct...