Question

A sphere of radius r is divided into four identical parts. find the total surface area of one part.​

Answer 1

Answer:

area of curved surface = 4πr²/4 = πr²

area of each semi-circular surface = πr²

area of 2 semicircular surface = 2×πr²/2 = πr²

therefore, T.S.A. = πr² + πr² = 2πr²

Answer 2

Answer:

The total surface area of a sphere is 4πr².

If we cut it one time from the middle then increase in the surface area is of 2πr².

If we rotate it 90° (doesn't matter whether clockwise or anti-clockwise), and cut it again from the middle then the increase would again be of 2πr².

Thus, the total surface area will be = 4πr² + 2πr² + 2πr² = 8πr²

Step-by-step explanation:

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