Question

In a cylinder radius is doubled and height is halved , c.s.a will be _______​

Answer 1

Step-by-step explanation:

The curved surface area will remain same. So, there is no change in the curved surface area of cylinder . Hence the curved surface area will remain same.

Answer 2

$\sf{\underline{ \underbrace{Understanding \: the \: Concept}}}$

Before solving this question, you must know what is the formula to find the Curved Surface Area (CSA) of a cylinder. So let's get started,

$\sf{\underline{ \underbrace{Formula}}}$

$\sf \blue{CSA \: of \: a \: cylinder = 2 \pi rh}$

where $\sf\purple{r}$ is the radius of the Cylinder and $\sf\purple{h}$ is the height of the Cylinder.

$\sf{\underline{ \underbrace{Solution :}}}$

Let $\sf\green{r_1}$ be the new radius that is 2 times the original radius and Let $\sf\green{h_1}$ be the new height that is half of the original height

$\sf {CSA \: of \: a \: cylinder = 2 \pi r_1h_1}$

$\sf {CSA \: of \: a \: cylinder = 2 \times \pi \times 2r \times \frac{h}{2}}$

$\sf {CSA \: of \: a \: cylinder = 2 \times \pi \times \cancel{ 2}r \times \frac{h}{ \cancel2}}$

$\sf \pink{ \underbrace{ \overbrace{CSA \: of \: a \: cylinder = 2 \pi rh}}}$

Hence, the CSA of the cylinder will remain the same