Question

Find the height and curved surface area if a cylinder whose diameter is 21 cm and total surface area is 1914 cm².​

Answer 1

Step-by-step explanation:

Given , diameter of a cylinder = 21 cm

Radius (r) = 21/2 cm

Total surface area of cylinder = 2πr(h+r).

According to the question,

$2\pi \: r(h + r) = 1914$

$= > 2 \times \frac{22}{7} \times \frac{21}{2} ( \frac{21}{2} + h) = 1914$

$= > 66( \frac{21}{2} + h) = 1914$

$= > \frac{21}{2} + h = \frac{1914}{66}$

$= > \frac{21}{2} + h = 29$

$= > h = 29 - \frac{21}{2}$

$= > h = \frac{58 - 21}{2}$

$= > h = \frac{37}{2}$

Height of a cylinder is 37/2 cm.

Curved Surface area of cylinder =2πrh sq. unit

$= 2 \times \frac{22}{7} \times \frac{21}{2} \times \frac{37}{2} \: sq.cm$

$= 11 \times 3 \times 37 \: \: \: sq.cm$

$= 1221 \: \: sq.cm$

Answer :- Height of a cylinder is 37/2 cm and Curved surface area of a cylinder is 1221 sq.cm.

Answer 2

Step-by-step explanation:

YOUR ANSER IS 1221CM².......