234X-CLASS MATHEMATICS90.700506363 XEm-.Area of its base is 254cm. Fin

1.	234X-CLASS MATHEMATICS90.700506363 XEm-.Area of its base is 254cm. Findi.7. The curved surface area of a cone is 1159volumednical above it. The radius of the base is
Answer» we have given that:curved surface area of cone = 1159 5/7 = 8118 / 7 cm² andarea of its base = 254 4/7 = 1782 / 7 cm² we have to find :-volume of cone = ? solution:-we know that:curved surface area of cone =πrlandarea of base =πr² andvolume of cone = 1/3×πr²handh =√ (l² - r²) where,r is radius , l is slant height , h is height of cone . According to given: => area of base = 1782 / 7 cm² =>πr² = 1782 / 7 => 22/7× r² = 1782 / 7 => 22 r² = 1782 => r² = 81 => r = 9 cm And,=> C.S.area = 8118 / 7 =>πrl = 8118 / 7 cm² => 22/7× 9× l = 8118 / 7 => 198 l = 8118 => l = 41 cm now,Height of cone;=> h =√(l² - r²) => h = √ (41² - 9² ) =√ (1681 - 81 ) =√ 1600 = 40 cm now,volume of cone = 1/3×π× r²× h => 1/3× 22/7× 9²× 40 => 22×81×40 / 21 => 3394.28 cm³ Answer

234X-CLASS MATHEMATICS90.700506363 XEm-.Area of its base is 254cm. Findi.7. The curved surface area of a cone is 1159volumednical above it. The radius of the base is

Answer»

we have given that:curved surface area of cone = 1159 5/7 = 8118 / 7 cm²

andarea of its base = 254 4/7 = 1782 / 7 cm²

we have to find :-volume of cone = ?

solution:-we know that:curved surface area of cone =πrlandarea of base =πr²

andvolume of cone = 1/3×πr²handh =√ (l² - r²)

where,r is radius , l is slant height , h is height of cone .

According to given:

=> area of base = 1782 / 7 cm²

=>πr² = 1782 / 7

=> 22/7× r² = 1782 / 7

=> 22 r² = 1782

=> r² = 81

=> r = 9 cm

And,=> C.S.area = 8118 / 7

=>πrl = 8118 / 7 cm²

=> 22/7× 9× l = 8118 / 7

=> 198 l = 8118

=> l = 41 cm

now,Height of cone;=> h =√(l² - r²)

=> h = √ (41² - 9² )

=√ (1681 - 81 )

=√ 1600 = 40 cm

now,volume of cone = 1/3×π× r²× h

=> 1/3× 22/7× 9²× 40

=> 22×81×40 / 21

=> 3394.28 cm³ Answer