Question

Find the number of metallic circular disc with 1.5 cm base diameter and of height 0.2 cm to be melted to form a right circular of height 10 cm and diameter 4.5 cm.

Answer 1

For Cone,

Base Diameter = 4.5 cm

Base radius, r = 2.25 cm

[as radius = diameter/2]

Height of cone, h = 10 cm

We know that,

Where, r is base radius and h is the height of the cone.

So,

Now, Disk is in shape of a cylinder

For a single disk

Base diameter = 1.5 cm

Base radius, r = 0.75 cm

[as radius = diameter/2]

Height, h = 0.2 cm

As we know,

Volume of a cylinder = πr²h

Where r is base radius and h is the height of cylinder

Volume of a disk = π(0.75)²(0.2) = (0.75 × 0.75 × 0.2) π cm³

Now,

So, 150 disks can be made by melting the cone.