Question

solve this question also

Answer 1

This question is related to Chapter:- Volume and Surface area.

As it is given that, A pen stand is made up of wood which has 4 depressions which is in the form of Cone.
In order to find the Volume of wood= Volume of Cuboid - Volume of 4 cones.

Now,

Volume of Cuboid = lbh cubic unit.
=> V = (15 x 10 x 3.5) cm^3
=> V = 525 cm^3

Hence, Volume of Cuboid = 525 cm^3

Again,

Volume of 1 Cone = 1/3 pi r^2 h

=> V =( 1/3 x 22/7 x 0.5 x 0.5 x 1.4) cm^3
=> V = 0.366667 cm^3

Now,
Volume of 4 such Cones = 4 x Volume of 1 Cone
=> Volume of 4 cones = (4 x 0.36667 0r 4 x 0.367) cm^3
=> Volume of 4 cones = 1.47 cm^3

Again,

Volume of Wood= Volume of Cuboid- Volume of 4 Cones.

=> V = (525-1.47) cm^3
=> V = 523.53 cm^3

As per in last part of question, It is asked about upto two decimal places.

=> Volume of Wood = 523.53 cm^3


Be Brainly

Answer 2

$\textbf{We have to find the volume of wood in stand}$

According to question we have given;

$\textbf{Length of cuboid (l) = 15 cm}$

$\textbf{Breadth of cuboid (b) = 10 cm}$

$\textbf{Height of cuboid (h) = 3.5 cm}$

So,

$\textbf{Volume of cuboid = l x b x h}$

= 15 × 10 × 3.5

= $525 cm{}^{3}$

Now,

$Volume of cone =$ ⅓ πr³

= 1/3× 22/7 × 0.5 × 0.5 × 1.4

= $0.367 cm{}^{3}$

$\textbf{Volume of 4 cones =}$ $\textbf{4 x Volume of one cone}$

= 4 × 0.367

= $1.47 cm{}^{3}$

Now...

$\textbf{Volume of wood in stand =}$
$\textbf{Volume of cuboid - Volume of 4 cones}$

= 525 - 1.47

= $523.53 cm{}^{3}$

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