Question

solids of right cylindrical shape are 49 cm and 35 cm high and their base
ameters are 16 cm, 14 cm respectively. Both are melted and moulded into a
le cylinder, 56 cm high. Find its base diameter.​

Answer 1

Volume of a solid right angle cylinder =base area×height of cylinder

V=(pi/4)d^2×h

r=base circle radius

h=height of cylinder.

As two cylinders are melted and moulded into another cylinder,there is no volume loss...hence,

volume of 1st cylinder+volume of 2nd cylinder =Volume of big cylinder

(pi/4)×d1^2×(h1)+(pi/4)×d2^2×(h2)= (pi/4)×D2×H

[pi/4 cancels both sides]

d1^2×h1+d2^2×h2=D^2×H

(16)^2×(49)+(14)^2×(35)=(D)^2×(56)

D=18.61cm