Multiple choice

Calculate the surface area of a sphere of radius $2.8$ cm.

  1. $98.56$ cm$^2$
  2. $68.56$ cm$^2$
  3. $38.56$ cm$^2$

  4. None of these
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A Correct answer
Explanation

The surface area of a sphere is given by 4 * pi * r^2. Using r = 2.8 and pi = 22/7, the calculation is 4 * (22/7) * 2.8 * 2.8 = 4 * 22 * 0.4 * 2.8 = 98.56 cm^2.

AI explanation

Using the surface area of a sphere formula, which is 4 times pi times radius squared, we multiply 4 by 22 divided by 7 and by 2.8 squared. The square of 2.8 is 7.84, so the calculation becomes 4 times 22 divided by 7 times 7.84, which simplifies to 88 times 1.12. This equals 98.56 square centimeters.

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