Chapter 12, Problem 20SGR

To determine

To find the radius of the given cylinder.

Answer to Problem 20SGR

  $r=7$ centimeters

Explanation of Solution

Given:

A cylinder Volume, $(V)=770$ cubic centimeters

Height, $(h)$$=5$ centimeters

Formula used:

Volume of the cylinder $=\pi r^{2}h$

where $r$ is the radius and $h$ is the height of the cylinder.

Calculation:

Volume of the cylinder $=\pi r^{2}h$ .

Now putting the value of volume and height,

  $\Rightarrow 770=\pi r^{2}h$

  $\Rightarrow 770=3.14\times r^2\times 5$

  $\Rightarrow r^2=\frac{770}{3.14\times 5}$

  $\Rightarrow r^2=49$

Taking square root on both the sides,

  $\Rightarrow r=\pm 7$

Now, $r\ne 7$ because radius cannot be a negative number.

So,

  $\Rightarrow r=7$ centimeters

Conclusion:

Hence, radius of the cylinder is 7 centimeters.