Question

C. Find the curved surface area and whole surface area of cylinder
whose diameter is 20m and height 21m​

Answer 1

Given:

• A cylinder whose diameter is 20m and height is 21m.

To Find:

• Curved surface area and total surface area = ?

Solution:

As we know,

$\large\sf\green{Radius={\frac{Diameter}{2}}}$

$\sf radius = \frac{20}{2} \\ \\ \sf radius = 10m$

Hence,Radius is 10m.

We know that,

$\large\sf\red{C.S.A = 2πrh}$

Where π is 22/7.

$\sf \implies \: c.s.a = 2 \times \frac{22}{7} \times 10 \times 21 \\ \\ \sf \implies1320 {m}^{2}$

Therefore,C.S.A is 1320m^2.

We know that,

$\large\sf\red{T.S.A=2πr(r+h)}$

$\sf \implies \: t.s.a = 2 \times \frac{22}{7} \times 10(10 + 21) \\ \\ \sf \implies \: t.s.a = 1948.5 {m}^{2}$

Hence,T.S.A = 1948.5m^2.