Question

Find the volume of frustum of cone of height 14cm and radii of upper ends and lower ends are 10cm and 6cm

Answer 1

Step-by-step explanation:

We have

r1=14cm;r2=6cm;h=6cm

Let l be the slant height of the frustum. 

Then l=h2−(r1−r2)2⇒l=36+64=10cm=π(r1+r2)

Lateral surface area =722×(14+6)cm2=628.57cm2

total surface area =π{r12+r22+(r1+r2)l}

                              =722×(196+36+20×10)cm2=1357.71cm2