Multiple choice

A circle of radius 5 mm is removed from the centre of a circular piece of metal of radius 7 mm.What is the area of the remaining portion?

  1. $\displaystyle 25\pi $
  2. $\displaystyle 49\pi $
  3. $\displaystyle 35\pi^{2} $
  4. $\displaystyle 24\pi $
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D Correct answer
Explanation

Area = pi * R^2 - pi * r^2 = pi * (7^2 - 5^2) = pi * (49 - 25) = 24 * pi.

AI explanation

The area of the remaining portion is the difference between the areas of the two circles, calculated using the formula Area = radius^2. The calculation is (7^2) - (5^2), which equals 49 - 25, giving a result of 24.

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