Question

How much iron is needed to make a rod of length 90 cm and diameter 1.4 cm?

Answer 1

length of rod , l = 90 cm
diameter of rod , d = 1.4 cm
so, radius of rod , r = 1.4/2 = 0.7 cm
volume of rod = πr²l
= 22/7 × 0.7 × 0.7 × 90
= 22 × 0.1 × 0.7 × 90
= 22 × 0.7 × 9
= 198 × 0.7
= 138.6 cm³

hence, 138.6 cm³ iron is needed to make a rod of length 90 cm and diameter 1.4 cm.

Answer 2

Hi ,

Dimensions of the rod ( cylinder shape ):

height ( h ) = 90 cm

diameter ( d ) = 1.4 cm

radius ( r ) = d/2 = 1.4/2 = 0.7 cm

Quantity of iron needed to make the rod

= volume of the rod

= πr²h

= ( 22/7 ) × ( 0.7 )² × 90

= 138.6 cm³

I hope this helps you.

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