Question

The radii of the ends ofa frustum of a cone 45 cm high and are 28 cm and 7 cm . Find its volume and the curved surface area

Answer 1

V. of Frus.

of cone = 1/3πh(Rsq.+rsq.+Rr)

1/3*22/7*45(28*28+7*7+28*7)
45 wll CT by 3
22*15/7(784+49+196)
now 22*15
330/7(1029)
now 1029/7=147
330*147=48,510cm cube (ANS.)

Answer 2

Answer:

Given,  

R = 28 cm

r= 7cm

H= 45cm

volume of frustum = $\pi$ /3H (R^2 + r^2 + R×r)

=>  $\pi$ /3×45 ( 28$^{2}$ +7$^{2}$ +28 ×7)

=> $\pi$/ 3×45( 784+49+196)

=> 22×15/7(784+49+196)

=> 22×15

330/7 (1029)

1029/7=147

330×147=48510$cm^{3}$

Total surface area = 48510$cm^{3}$

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@GauravSaxena01