Question

A cone of radius 4cm is divided into 2 parts by drawing a plane through the mid point of its axis and parallel to its base compare the volumes of 2 parts

Answer 1

Answer:

The ratio of their volumes are 1:7

Step-by-step explanation:

Now,

In ΔPQR&ΔPBC,

∠QPR=∠BPC               (Common)

Also,

∠PQR=∠PBC               (Corresponding Angles)

ΔPQR~ΔPBC               (By AA similarity criterion)

So,

PQ/PB=QR/BC=PR/PC

1/2=QR/BC                            (PQ=BQ)

BC=2QR

But,

BC=4

So,

QR=4/2

    =2cm

1/3πr²h/1/3πh(R²+r²+Rr)           (∵The cone is cut in the mid point of its height)

=4/(16+4+8)

=4/28

=1/7

The ratio of their volumes are 1:7