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30 circular plates, each of radius 14 cm and thickness 3cm are placed one above the another to form a cylindrical solid. Find the total surface area.

Solution:

Given, 30 circular plates each of radius 14 cm and thickness 3 cm are placed one above the other to form a cylindrical solid.

We have to find the total surface area.

Given, radius of one circular plate = 14 cm

Thickness of one circular plate = 3 cm

Now, radius of base of cylinder r = 14 cm

Height of cylinder = 30 × thickness of one circular plate

= 30(3)

h = 90 cm

Total surface area of cylinder = 2πr(h+r)

Where, r is the radius of the cylinder

h is the height of the cylinder

= 2π(14)(14 + 90)

= 28π(104)

= 28(22/7)(104)

= 4(22)(104)

= 88(104)

= 9152 cm²

Therefore, the total surface area of cylinder is 9152 cm²

✦ Try This: 20 circular plates, each of radius 24 cm and thickness 5 cm are placed one above the other to form a cylindrical solid. Find the total surface area.

☛ Also Check: NCERT Solutions for Class 9 Maths Chapter 13

NCERT Exemplar Class 9 Maths Exercise 13.4 Problem 8(i)

30 circular plates, each of radius 14 cm and thickness 3cm are placed one above the another to form a cylindrical solid. Find the total surface area.

Summary:

30 circular plates, each of radius 14 cm and thickness 3cm are placed one above the other to form a cylindrical solid. The total surface area is 9152 cm²

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