Question

1) Find the volume of a cone whose radius is 9 cms and height  8.1 cms 

2) Find the volume of a cylinder whose base area is 45m2  and height is 30 cms.​

Answer 1

Answer:

given,

r=9 and h=8.1

then

volume= 1/3(pi.r².h)

1/3(3.14*81*8.1)

686.71

Answer 2

1. Find the volume of a cone whose radius is 9 cms and height  8.1 cms

Given :

• Radius = 9cm
• Height = 8.1 cm

To Find :

• Volume of a cone

Solution :

⇒Volume of a cone = 1/3 × πr²h

⇒ Volume of a cone = 1/3 × 22/7 × 9 × 9 × 8.1

⇒ Volume of a cone = 22 × 9 × 9 × 8.1 / 7×3

⇒ Volume of a cone = 22 × 9 × 9 × 8.1 / 21

⇒ Volume of a cone = 14434.2 / 21

⇒ Volume of a cone = 687.34cm³

•°• Hence, Volume of a cone = 687.34cm³

_____________________________

2. Find the volume of a cylinder whose base area is 45m2 and height is 30 cms.

Given :

• Area = 45m²
• Height = 30cm

To Find :

• Volume of a cylinder

Solution :

First we've to find r.

The curved surface area of the cylinder in CSA = 2πrh

→ CSA = 2πrh

→ 45 = 2 × 22/7 × r × 30

→ r = 45 / 2 × 22/7 × 30

→ r = 4.1

The radius of the cylinder = 4.1

Now, We've π = 22/7, r = 4.1, h= 30

⇒ Volume of a cylinder = πr²h

⇒ Volume of a cylinder = 22/7 × 4.1 × 4.1 × 30

⇒ Volume of a cylinder = 1584.9 cm³

•°• Hence, Volume of a cylinder = 1584.9 cm³