Question

find the volume of a cone if the radius of its base is 1.8 cm and its perpendicular height is 4cm.
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Answer 1

GivEn:-

• Radius of Cone = 1.8 cm

• Height of cone = 4 cm

To find:-

• Volume of cone.

SoluTion:-

GivEn that,

✇ Radius (r) of cone is 1.8cm and its perpendicular height (h) is 4cm.

As we know that,

★ ${\underline{\boxed{\sf{\purple{Volume_{(cone)} = \dfrac{1}{3} \times \pi r^2 h}}}}}$

✩ Now, Put the givEn values -

$\dashrightarrow\sf V = \dfrac{1}{3} \times \dfrac{22}{7} \times 1.8 \times 1.8 \times 4$

$\dashrightarrow\sf V = \dfrac{1}{3} \times \dfrac{22}{7} \times 1.8 \times 1.8 \times 4$

$\dashrightarrow\sf V = \dfrac{1}{3} \times \dfrac{22}{7} \times 12.96$

$\dashrightarrow\sf V = \dfrac{1}{ \cancel{3}} \times \dfrac{22}{7} \times \cancel{12.96}$

$\dashrightarrow\sf V = \dfrac{22}{7} \times 4.32$

$\dashrightarrow\sf \red{V = 13.57\;cm^3}$ ★

$\therefore\;\sf \underline{Volume\;of\;cone\;is\;13.57\;cm^3}$

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Answer 2

Given ,

Radius of cone (r) = 1.8 cm

Height of cone (h) = 4 cm

We know that , the volume of cone is given by

$\boxed{ \sf{Volume = \frac{\pi {(r)}^{2} h}{3} }}$

Thus ,

$\sf \mapsto Volume = \frac{1}{3} \times \frac{22}{7} \times {(1.8)}^{2} \times 4 \\ \\\sf \mapsto Volume = \frac{22 \times 3.24 \times 4}{3 \times 7} \\ \\\sf \mapsto Volume = \frac{22 \times 1.08 \times 22}{7} \\ \\ \sf \mapsto Volume = \frac{4.32 \times 22}{7} \\ \\\sf \mapsto Volume = \frac{95.04}{7} \\ \\ \sf \mapsto Volume = 13.5 \: \: {cm}^{3}$

Therefore ,

The volume of cone is 13.5 cm³