Question

The radius of a cylinder is 4.2 cm and its height is 16 cm. There are discs of diametre 1.4 cm and height 0.2 cm. How many discs to make up for the cylinder? plz ans i will mark brainliest
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Answer 1

Answer:

Height of the solid copper cylinder = 16 cm. Volume of the cylinder = pi x r x r x h = 3.14 x 4.2 x 4.2 x 16 = 886.23 cbcm. Volume of one disc of diameter 1.4 cm and thickness 0.2 cm = 3.14 x 0.7 x 0.7 x 0.2 = 0.307cbcm.

Answer 2

Answer:

radius of solid copper cylinder , R = 4.2 cm

height of solid copper cylinder , H = 16 cm

so, volume of solid copper cylinder = πR²H

= 22/7 × 4.2 × 16

= 22 × 0.6 × 16

= 22 × 9.6

= 211.2 cm²

thickness of disc , h = 0.2 cm

radius of disc , r = diameter/2 = 1.4/2 = 0.7 cm

now, volume of disc = πr²h

= 22/7 × 0.7 × 0.2

= 22 × 0.1 × 0.2

= 0.44 cm²

\textbf{\underline{number of discs}}=\frac{\text{volume of cylindrical copper solid}}{\text{volume of each disc}}

number of discs

=

volume of each disc

volume of cylindrical copper solid

= 211.2/0.44 = 480

hence, number of discs = 480