A solid cone of height 12 cm and radius 9 cm is recast into a solid sphere. Calculate the surface area of the sphere

Answers

$\frac{1}{3}\pi r^2h \; =\;\frac{4}{3}\pi R^3$ ;

$r^2h\; =\; 4R^3$

81 x 12 = 4R<sup>3</sup>

$3\sqrt{\frac{81\times 12}{4}}$ = R

R = 6.24 cm

Area of sphere = 4

$\pi R^2$

= 4 x 3.142 x 6.24 x 6.24

= 489.4 cm

$^2$

johnmulu answered the question on March 8, 2017 at 05:41

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