Multiple choice

If the radius of the circle is increased by 100% then the area is increased by

  1. 100%

  2. 200%

  3. 300%

  4. 400%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If radius increases by 100%, new radius = 2r. New area = pi * (2r)^2 = 4 * pi * r^2. The increase is 4 * Area - Area = 3 * Area, which is 300%.

AI explanation

Increasing the radius by 100 percent doubles the radius, so the new area becomes pi times the quantity 2r squared, which is 4 times pi r squared. The original area was pi r squared, meaning the new area is 400 percent of the original. The increase is 400 percent minus the original 100 percent, resulting in a 300 percent increase.

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