Multiple choice

The volume of the hemisphere is $\displaystyle 2100{ cm }^{ 3 }$. Find its radius. (Round off your answer to the nearest whole number).

  1. $12$ cm
  2. $10$ cm
  3. $11$ cm
  4. $9$ cm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The volume of a hemisphere is (2/3) * pi * r^3. Setting (2/3) * pi * r^3 = 2100 results in r^3 = 2100 * 3 / (2 * 3.14159) which is approximately 1002.67. The cube root of 1002.67 is approximately 10.008, which rounds to 10.

AI explanation

The formula for the volume of a hemisphere is V = (2/3) * pi * r^3. Rearranging to find the radius gives r^3 = (3V) / (2 * pi). Substituting the volume of 2100 cm^3 and pi as 3.14 gives r^3 = 6300 / 6.28, which equals 1003.18. Taking the cube root gives a radius of 10.01 cm. The radius rounded to the nearest whole number is 10 cm.

Keep practicing — related questions