Question

the curved surface area of a cylindrical rod is 132 cm². find its length if its diameter is 0.35 cm

Answer 1

Diameter of cylinder = 0.35 cm

Radius = 0.35 / 2 cm

CSA = 132

=> 2 pi r*h = 132

=> 2*22 *0.35 * h / 7* 2 = 132

=> h = 132 * 7* 2 / 2* 22 * 0.35

=> h = 6/ 0.05

=> h = 600 / 5

=> h = 120 cm

Length of rod = 120 cm

= 1.2 m

Answer 2

$curved \: surface \: area = 2\pi \: rh \\ d = 0.35 \\ r = \frac{0.35}{2} = 0.175 \\ 2 \times \frac{22}{7 } \times 0.175 \times h = 132 \\ \frac{44}{7} \times \frac{175}{1000} \times h = 132 \\ \\ \frac{11}{10} \times h = 132 \\ h = 132 \times \frac{10}{11} = 12 \times 10 = 120cm$