Question

The curved surface area of a cylindrical pillar is 176 m? and its volume is 352 m². Find the ratio of its radius to its height. (Use ∏= 22/7)

• A. 3:5
• B. 4:7
• C. 3:4
• D. 2:3

Answer 1

Answer:

B. 4:7

For a cylinder:

Curved Surface Area (CSA) $= (2\pi rh = 176)$
Volume $= (\pi r^2 h = 352)$

Divide volume by CSA:
$\frac{\pi r^2 h}{2\pi rh} = \frac{352}{176}$

$\frac{r}{2} = 2$

$\Rightarrow r = 4$
Now substitute in CSA:

$2\pi rh = 176$
$2 \times \frac{22}{7} \times 4 \times h = 176$

$\frac{176}{7} \times h = 176$

h = 7

So, ratio (r : h = 4 : 7)

Final Answer: 4 : 7