What is the total surface area of a right circular cone of height 14 cm and base

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Question
What is the total surface area of a right circular cone of height 14 cm and base radius 7 cm?
Options
A. 344.35 cm²
B. 462 cm²
C. 498.35 cm²
D. None of these

Correct Answer

498.35 cm²

Explanation
h = 14 cm, r = 7 cm.

So, l = √(7)² + (14)² = √245 = 7√5 cm.

∴ Total surface area

= Πrl + Πr²

=	❨	22	x 7 x 7√5 +	22	x 7 x 7	❩cm²
		7		7

= [154(√5 + 1)] cm²

= (154 x 3.236) cm²

= 498.35 cm².

Volume and Surface Area problems

Search Results

1. The curved surface area of a cylindrical pillar is 264 m² and its volume is 924 m³. Find the ratio of its diameter to its height.
Options
A. 3 : 7
B. 7 : 3
C. 6 : 7
D. 7 : 6

2. A right triangle with sides 3 cm, 4 cm and 5 cm is rotated the side of 3 cm to form a cone. The volume of the cone so formed is:
Options
A. 12Π cm³
B. 15Π cm³
C. 16Π cm³
D. 20Π cm³

3. How many bricks, each measuring 25 cm x 11.25 cm x 6 cm, will be needed to build a wall of 8 m x 6 m x 22.5 cm?
Options
A. 5600
B. 6000
C. 6400
D. 7200

4. A boat having a length 3 m and breadth 2 m is floating on a lake. The boat sinks by 1 cm when a man gets on it. The mass of the man is:
Options
A. 12 kg
B. 60 kg
C. 72 kg
D. 96 kg

5. A cistern 6m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is:
Options
A. 49 m²
B. 50 m²
C. 53.5 m²
D. 55 m²

6. 50 men took a dip in a water tank 40 m long and 20 m broad on a religious day. If the average displacement of water by a man is 4 m³, then the rise in the water level in the tank will be:
Options
A. 20 cm
B. 25 cm
C. 35 cm
D. 50 cm

7. 66 cubic centimetres of silver is drawn into a wire 1 mm in diameter. The length of the wire in metres will be:
Options
A. 84
B. 90
C. 168
D. 336

8. A hall is 15 m long and 12 m broad. If the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls, the volume of the hall is:
Options
A. 720
B. 900
C. 1200
D. 1800

9. A cistern of capacity 8000 litres measures externally 3.3 m by 2.6 m by 1.1 m and its walls are 5 cm thick. The thickness of the bottom is:
Options
A. 90 cm
B. 1 dm
C. 1 m
D. 1.1 cm

10. A large cube is formed from the material obtained by melting three smaller cubes of 3, 4 and 5 cm side. What is the ratio of the total surface areas of the smaller cubes and the large cube?
Options
A. 2 : 1
B. 3 : 2
C. 25 : 18
D. 27 : 20

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