A circular shaped ball with a diameter or radius is called a sphere.A diameter which is a straight line through the center of a sphere and with the end points on the boundary is called its diameter.
The section of the sphere by the plane is called a hemisphere. Let’s see how to find the area of Hemisphere.
Formula of Surface area of Hemisphere.
Total Surface area of Sphere (TSA) = 4πr2
Curved Surface area of Hemisphere(CSA) = 2πr2
Total Surface area (TSA) = 3πr2
Surface area of Hemisphere Formula Examples
Question: The radius of a red balloon increases from 6cm to 12 cm when the air is pumped into it. Calculate the ratios of the surface areas of the balloon in both the cases.
Solution: Hemisphere 1 – r = 6cm
Hemisphere 2 – r = 12 cm
TSA – 1 = 3πr2
TSA – 2 =3π(12)2
Let’s find the ratio: TSA1 /TSA2, = ½
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