Question

1. Find the volume of a right circular cylinder of radius 2.8 m and height 3.5 m.
2. Find the volume of a cylinder having a height of 21 cm and an area of base as 138
cm².
3. A hollow cylindrical tube is 3.5 m long. If its inner and outer radii are 7 cm and
7.7 cm respectively, then
find the volume of the material used in making the pipe.​

Answer 1

Answer:

Step-by-step explanation:

1) 30.8 cm^2

2) 2898cm^2

3) 102703.13 cm^2

4) 5m, 154m^2

Answer 2

Step-by-step explanation:

1) volume = π x (r)^2 x h

volume = π x (2.8)^2 x 3.5

volume = 22/7 x 7.84 x 3.5

volume = 86.24 m cube

2) Area of base = 138cm ^2

Area of base = π (r)^2

Area of base = 22/7 x (r)^2

138 = 22/7 x (r)^2

138 x 7/22 = (r)^2

43.90 = (r)^2

r =√43.90

r = 6.625 cm

volume of cylinder = π (r)^2 h

volume = 22/7 x (6.625)^2 x 21

volume = 2896.78125 cm cube

3) Volume of hollow cylinder = π [ (R)^2 - (r)^2 ] h

Volume = 22/7 x [ ( 7.7)^2 - (7) ^2] h

volume = 22/7 x [ 59.29 - 49 ] h

volume = 22/7 x 10.29 x h

volume = 32.34 x 3.5 x 100 cm

volume = 11319 cm cube or 0.011319 m cube