Question

a cone of radius 10 cm is divided into two parts by a plane parallel to its base through the midpoint of its height compare the volumes of the two parts.
see who will give answer first..

i will mark as brainliest..

Answer 1

radius of cone = 10cm
radius of frustum= R=10,r= 5cm, h= h/2

ratio of volume = volume of cone/ volume of frustum.
formula for volume of cone= 1/3 pi r^2h
formula for volume of frustum= 1/3pih[R^2 + r^2 + Rr]

ratio of volume = volume of cone/volume of frustum

1/3 × pi × h/2 × r^2
-----------------------------------------
1/3 ×pi × h/2 [R^2+ r^2+Rr]

cancelling out 1/3 pi h/2

r^2
---------------------------
R^2 + r^2 + Rr

(5)^2
-----------------------
(10)^2 + (5)^2 + (5)(10)


25
------------------------
100 + 25 + 50

25/175 = 1/7

therefore the ratio becomes 1:7

hope it helps you.
please mark it as brainliest.

Answer 2

hope it will help you