Question

find the volume of a cylinder whose height and radius 21 cm and 2 cm respectively​

Answer 1

Answer:

2770.88 cm cube

Step-by-step explanation:

volume of cylinder = pie r^2 h

since radius =21 cm

and height =2 cm

the volume of cylinder= 22/7*21*21*2

                                     =2770.88 cm^cube

Answer 2

Answer:

$84\pi cm^3$ or $264 cm^3$ to 3 significant figures

Step-by-step explanation:

To find the volume, we multiply the cross-sectional area by the height.

For a cylinder, the formula is: $V=\pi r^2 h$, where $V$ is the volume, $r$ is the radius and $h$ is the height.

In this case, the cross-section of a cylinder is simply a circle. Imagine getting a cylinder and placing it flat on a cutting board and cutting it parallel to its base. Thus, we end up with a circle.

Since a circle is the cross-section of a cylinder, we need to find the area of the circle and then multiply it by the height of the cylinder.

To find the area of the circle, we use the formula:

Area of a circle = $\pi r^2$

Where the radius, $r$, is 2cm.

Thus, area of the circle = $\pi *2^2=4\pi cm^2$

Now, we just have to multiply this by the height of the cylinder, which is 21 cm:

$4\pi *21=84\pi cm^3$

Thus, we obtain our answer of $84\pi cm^3$ or $264 cm^3$ to 3 significant figures.