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

Open in App

Solution

Each one of those metallic disk is also a cylinder (just a very very short one), and its volume is $V = π r^{2} h = π (0.75)^{2} \times 0.2 = \frac{9 π}{80} c m^{3}$

The right circular cylinder has volume $V^{'} = π (2.25)^{2} \times 10 = \frac{405 π}{8} c m^{3}$

So, the number of metallic discs $= \frac{V o l u m e o f r i g h t c i r c u l a r c y l i n d e r}{V o l u m e o f e a c h m e t a l l i c d i s c}$

$= \frac{(\frac{405 π}{8})}{(\frac{9 π}{80})} = 450$

Suggest Corrections

Similar questions

Q. Question 14
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 cylinder of height 10 cm and diameter 4.5 cm

Q. Find the number of coins, 1.5 cm is diameter and 0.2 cm thick, to be melted to form a right circular cylinder of height 10 cm and diameter 4.5 cm.

Q. The number of coins 1.5 cm in diameter and 0.2 cm thick to be melted to form a right circular cylinder of height 10 cm and diameter 4.5 cm is
(a) 540
(b) 450
(c) 380
(d) 472

The number of coins of $1.5 c m$ in diameter and $0.2 c m$ thick, to be melted to form a right circular cylinder of height $10 c m$ of diameter $4.5 c m$ is

(a) $540$ (b) $450$ (c) $380$ (d) $472$

Q. If some coins each of diameter

1.5 c m

and thickness

0.2 c m

are melted and a right circular cylinder of height

10 c m

and diameter

4.5 c m

is made, then find the number of coins required to make the right circular cylinder

Join BYJU'S Learning Program