Question

The surface area of a sphere of radius 5 cm is 5 tme the curved surface area of a cone of radius 4 cm. Find the height and volume of the cone.

Answer 1

may the answer is right

Answer 2

surface area of a sphere=4$\pi r^{2}$ and r=5
⇒4*22/7*5*5=2200/7
NOW, THE Curved surface area of a cone of radius 4 cm = 2200/7*1/5=440/7
BUT Curved surface area of a cone= $\pi Rl$=440/7
⇒22/7*4*l=20*22/7
⇒4l=20
⇒l=5 cm
THEREFORE $H ^{2}$=$l ^{2} -R ^{2}$
=$H ^{2}$=25-16
⇒H=3
THEREFORE VOLUME=1/3*$\pi R^{2}H$
=1/3*22/7*4*3
=88/7
=12.57 $cm^ {3}$