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Surface Areas and Volumes — MATHS STD 9 — Question

Rajasthan BoardEnglish MediumSTD 9MATHSSurface Areas and Volumes1 Mark
Question
A solid metallic cylinder of base radius 3cm and height 5cm is melted to make n solid cones of height 1cm and base radius 1mm. The value of n is.
✓

Answer

  1. 13500
Solution:
Radius of cylinder = 3cm.
Height = 5cm
Radius of cone= 1mm = 0.1cm
Height = 1cm
Volume of cylinder = number of cones × Volume of cone
$\pi\text{R}^2\text{h}=\text{n}\times\frac{1}{3}\pi\text{r}^2\text{h}$
$\pi32\times5=\text{n}\times\frac{1}{3}\pi\times0.1^2\times1$
$45=\text{n}\times\frac{1}{3}\times(.1)^2\times1$
$45=\text{n}\times\frac{1}{100}$
$\text{n}=13500$
$13500$

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