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Question:

If the radius of a circle is increased by 10?

12.1πr²

1.21π²

121πr²

None of the given three.

Solution:

The correct option is D None of the given three.
Assume the radius of the original circle = r
Area = πr²
As the radius is increased by 10, the new radius will be r + 10.
New area = π(r + 10)² = π(r² + 20r + 100)
The increase in area is π(r² + 20r + 100) - πr² = π(20r + 100)
None of the given options match this increase in area. Therefore, the correct answer is 'None of the given three.'