09
Dec
Question 4: The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases.
Sphere – Surface area
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Surface area of sphere = 4πr²
r = radius of sphere
Lateral or curved surface area of hemisphere = 2πr²
Total surface area of hemisphere = 2πr² + πr² = 3πr²
r = radius of sphere
What is Area / Surface area / Volume
It is recommended to understand the core concept of area, surface area and volume before we attempt any question based on these concepts.
Chapter 13 – Surface areas and Volumes
Concepts
- Area / Surface area / Volume – Introduction
- Surface Area of Cube and Cuboid
- Volume Of Cuboid and Cube
- Surface Area of Right Circular Cylinder
- Volume and capacity of Cylinder
- Right circular Cone
- Surface Area of Right circular Cone
- Volume of Cylinder vs Cone
- Litres and Cubic centimetre (cm³)
- Cubic meters to litres
