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prakhar mahendra

· started a discussion

· 1 Months ago

height of cone is not calculated

Question:
A solid cone of height 9 cm, with diameter of its base 18 cm, is cut out from a wooden solid sphere of radius 9 cm. The percentage of wood wasted is –
Options:
A) 25
B) 30
C) 50
D) 75
Solution:

Hieght of cone is 9cm

radius of cone is 9cm

therefore volume of cone will be=1/3πr²h

                                             =πx3 x 9 x 9

                                             =243π

now volume of sphere is =4/3πr³

                                    =4/3*π*9 x 9 x 9=972π

therefore volume of wood left=972π-243π=729π

therefore percentage of wood waste=729π/972π x 100

                                                   =75% 

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