Question

a drinking glass in the shape of a frustum of a cone of height 14cm.the diameter of its two circular ends are 4cm and 2cm find the capacity of the glass

Answer 1

Volume of frustum = 1/3×22/7×14(1^2+2^2+1+×2)

=44/3(7)

=308/3

=102.67

Answer 2

We have

R = 2 cm ,

r = 1 cm &

h = 14 cm

Volume of frustum

$= \frac {1}{3} \pi h ( R² + r² + Rr ) \\\\\ = \frac {1}{3} \pi \times 14 (2²+1²+2) \\\\\ = \frac {1}{3} \times \frac {22}{7} \times 14 \times 7 \\\\\ = 102 \frac{2}{3} ~ cm²$