Question

The height and radius of a cylinder are $7.5$ cm and $3.5$ cm respectively. Find the ratio of its total surface area and curved surface area.

Answer 1

Given that

$Radius\left(r\right)=3.5cm$

$Height\left(h\right)=7.5cm$

Curved Surface Area of cylinder $=2\pi rh$

$=2\times \frac{22}{7}\times 3.5\times 7.5$

Curved Surface Area of cylinder$=165c{m}^2$

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

$=2\times \frac{22}{7}\times 3.5\times (7.5+3.5)$

Total Surface Area of cylinder $=242c{m}^2$

$\therefore$ The ratio of Total Surface Area and Curved Surface Area of cylinder $=242:165$

$=22:15$

Hence, the required ratio is $22:15$