The radius and height of a cone are in the ratio 4 : 3. The volume of the cone is 539/2 cm3 . Find its curved surface area.
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radius = 4x
height = 3x
volume = 539/2 cm³
but volume of cone = 1/3 pi r² h
539/2 = 1/3. 22/7.16x² . 3x
539/2.3.7/22 = 48x³
∴x³=7.7.7/4.4.4
x = 7/4
∴surface area of cone =pi r l
but l=√h²+r²
√9x²+16x²
√25x²
5x
5.7/4
35/4
surface area = 22/7. 7/4 . 35/4
=385/8 units²
height = 3x
volume = 539/2 cm³
but volume of cone = 1/3 pi r² h
539/2 = 1/3. 22/7.16x² . 3x
539/2.3.7/22 = 48x³
∴x³=7.7.7/4.4.4
x = 7/4
∴surface area of cone =pi r l
but l=√h²+r²
√9x²+16x²
√25x²
5x
5.7/4
35/4
surface area = 22/7. 7/4 . 35/4
=385/8 units²
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