Question

19.8.
3. A cylindrical pillar is 50 cm in diameter and 3.5 min height. Fin
curved surface of the pillar at the rate of 12.50 per m²
4. It is required to make a closed cylindrical tank of height 1 ma
from a metal sheet. How many square metres of the sheet are
5. A solid cylinder has total surface area of 462 cm². Its curved s
its total surface area. Find the radius and height of the cylind
6. The total surface area of a hollow cylinder which is open fro
area of base ring is 115.5 sq.cm and height 7 cm. Find the th
7. Find the ratio between the total surface area of a cylinder to it
that its height and radius are 7.5 cm and 3.5 cm.​

Answer 1

Answer:

13. pillar is in the form of cylinder

curved surface area of a pillar = 2πrh

height = 3.5m

diameter = 50 cm

radius = 50 /2= 25 cm= 0.25m

Curved surface area of a pillar= 2πrh

= 2 *22/7*0.25*3.5

=5.5m square

cost of painting of 1m =Rs.12.50

cost of total surface = 5.5 * 12.50

= Rs. 68.75