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.


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.


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