Chapter 12.9, Problem 15IP

To determine

To find : Surface Area of given figure.

Answer to Problem 15IP

  $6120.37{\text{ cm}}^{\text{2}}$

Explanation of Solution

Given information :

The given information is,

  

We know that

  $r_1$ is the radius of $1^{\text{st}}$ cylinder and $h_1$ is the height.

  $r_2$ is the radius of the $2^{\text{nd}}$ cylinder and $h_2$ is the height.

Length ( $l$ ) = $60$ cm, Breadth ( $b$ ) = $20$ cm, height ( $h$ ) = $150$ cm,

  $\begin{array}{l}{r}_1=\frac{7}{2}\text{cm},h_1=15\text{cm,}\\ {\text{r}}_{\text{2}}=10\text{ cm, }{h}_2=7\text{ cm}\end{array}$

Formula Used:

Surface area of cylinder = $2\pi r(r+h)$

Surface area of cuboid = $2(lb+bh+hl)$

Calculation :

Surface Area of given figure

  $\begin{array}{l}=2(1200+300+900)+2\times 3.14\times \frac{7}{2}\times 15+2\times 3.14\times 10(10+7)\\ =4800+329.7+1067.6\\ =6197.3\end{array}$

Surface Area of given figure

  $\begin{array}{l}=6197.3-2\times 3.14\times {\left(\frac{7}{2}\right)}^2=6120.37{\text{ cm}}^{\text{2}}\\ =6120.37{\text{ cm}}^{\text{2}}\end{array}$