Question

9.find the height of a cylinder whose radius is 7cm and the curved surface area is
220 cm 2
O 4 cm
5 cm
O 6 cm
O 7 cm​

Answer 1

Answer:

5 cm

Step-by-step explanation:

Curved Surface area = 220

2πrh = 220

2*22/7*7*h = 220

h = 220*7/2*22*7

h = 5 cm

Answer 2

Step-by-step explanation:

Question :-

• Find the height of cylinder whose radius is 7 cm and curved surface area is 220 cm².

To Find :-

• Height of cylinder.

Solution :-

Given :

• Radius = 7 cm
• CSA = 220 cm²

By using the formula,

${\longrightarrow{\sf CSA\ of\ cylinder\ =\ 2 \pi rh}}$

Where,

• r = radius of the cylinder
• h = height of the cylinder

According to the question, by using the formula, we get :

${\longrightarrow{\sf CSA\ of\ cylinder\ =\ 2 \pi rh}}$

${\longrightarrow{\sf 220\ =\ 2 \times \dfrac{22}{7} \times 7 \times h}}$

${\longrightarrow{\sf 220\ =\ 2 \times \dfrac{22}{\cancel7} \times \cancel7 \times h}}$

${\longrightarrow{\sf 220\ =\ 2 \times 22 \times h}}$

${\longrightarrow{\sf 220\ =\ 44h}}$

${\longrightarrow{\sf \dfrac{220}{44}\ =\ h}}$

${\longrightarrow{\sf 5\ =\ h}}$

${\longrightarrow{\sf h\ =\ 5\ cm}}$

∴ Hence, height of cylinder is 5 cm.

More To Know :-

$\begin{array}{|c|c|c|}\cline{1-3}\bf Shape&\bf Volume\ formula&\bf Surface\ area formula\\\cline{1-3}\sf Cube&\tt l^3}&\tt 6l^2\\\cline{1-3}\sf Cuboid&\tt lbh&\tt 2(lb+bh+lh)\\\cline{1-3}\sf Cylinder&\tt {\pi}r^2h&\tt 2\pi{r}(r+h)\\\cline{1-3}\sf Hollow\ cylinder&\tt \pi{h}(R^2-r^2)&\tt 2\pi{rh}+2\pi{Rh}+2\pi(R^2-r^2)\\\cline{1-3}\sf Cone&\tt 1/3\ \pi{r^2}h&\tt \pi{r}(r+s)\\\cline{1-3}\sf Sphere&\tt 4/3\ \pi{r}^3&\tt 4\pi{r}^2\\\cline{1-3}\sf Hemisphere&\tt 2/3\ \pi{r^3}&\tt 3\pi{r}^2\\\cline{1-3}\end{array}$