Question

1) A wooden cylinder of length 21 cm has a diameter of 8 cm. what is the volume of the cylinder? ​

Answer 1

Answer:

Given, height of the cylindrical groove h = 21 cm

Diameter of the lead = 3 cm

So, radius of the lead = 3/2 = 1.5 cm

Now, volume of the lead = πr2 h

                                   = (22/7) * (1.5)2 * 21

                                   = 22 * 1.5 * 1.5 * 3

                                   = 148.50 cm3

So, the volume of lead = volume of groove = 148.50  

Again, given that groove is filled with lead.

Now, outer diameter of the wooden cylinder = 12 cm

So, outer radius of the wooden cylinder = 12/2 = 6 cm

and height h = 21 cm

Now, volume of wooden cylinder = πr2 h

                                               = (22/7) * 62 * 21

                                               = 22 * 36 * 3

                                               = 2376 cm3

Now, volume of wood = volume of wooden cylinder without groove - volume of groove

                               = 2376 - 148.50

                               = 227.5 cm3

PLZ MARK ME  AS BRAINIEST

Answer 2

Height = $\sf{\color{olive}21 cm }$

Radius = $\sf{{\color{olive}{\dfrac{8}{2}} = 4 ~cm}}$

Volume = $\sf{{\color{navy} \pi r^2 h }}$

⇒ $\sf{{\dfrac{22}{{\bcancel{7}}} \times 16 \times {\bcancel{21}^3}}}$

⇒ $\sf{{22 \times 16 \times 3 }}$

⇒ $\sf {\color{teal}{1,056~cm^3}}$