Chapter 12.4, Problem 18PSB

Solution

To Calculate: The volume of cement needed

The required volume of cement is $220\pi$

Given information:

Radius of big cylinder (R) = $6$

Radius of small cylinder (r) = $5$

Height of cylinder (h) = $20$

Formula used:

Here, we are using the formula:

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

(Where, “r” is radius and “h” is height)

Calculation:

Here, volume of big cylinder = $\pi R^{2}h$

➜ $\pi \times {\left(6\right)}^2\times 20$

➜ $720\pi$

And, volume of small cylinder = $\pi r^{2}h$

➜ $\pi \times {\left(5\right)}^2\times 20$

➜ $500\pi$

Now, required volume = $720\pi -500\pi$

➜ $220\pi$

Conclusion: Hence, the required volume of cement is $220\pi$