a cone of height 8 m has a curved surface area 188.4 square metres. find its volume (take pi = 3.14

Asked by nmenghani | 11th Jan, 2010, 08:59: PM

Expert Answer:

CSA of a cone = πSR = 188.4 m2

S = 188.4/(3.14xR) = 60/R

R2 = (S2-h2)

R2 = (60/R)2- 82

R4 + 64R2 - 3600 = 0

r2 + 64r - 3600 = 0         ... where r = R2

r = [-64±(4096+4x3600)]/2

= [-64±136]/2

Hence r = 36, and R = 6 m.

Volume of a cone = πR2h/3 = (3.14x6x6x8)/3 = 301.44 m3.

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Answered by  | 30th Nov, 2017, 12:41: PM