Question

A log of wood is cylindrical in shape. The radius and height of the log is 2 cm and 12 cm respectively. What area needs to be covered if the log has to be painted completely?

• A. $52c{m}^2$
• B. $176c{m}^2$
• C. $120c{m}^2$
• D. $136c{m}^2$

Answer 1

The correct option is B $176c{m}^2$

Given: r = 2 cm ; h = 12 cm

Total area that needs to be painted = Total Surface Area

$\text{Total Surface Area}$ = $\text{Curved Surface Area}+2\times \text{Base Area}$

$=2\pi rh+2\pi r^2$

$=2\pi r(h+r)$

$=2\times \frac{22}{7}\times 2(12+2)$

$=\frac{44}{7}\times 2\times 14$

$=176c{m}^2$

Hence the total area that needs to be painted $=176c{m}^2$