Multiple choice

A top is of the shape of a cone over a hemisphere. The radius of the hemisphere is 3 cm. The total height of the top is 7 cm. What is the total area of the top?

  1. 103.7 sq. cm

  2. 21.45 sq. cm

  3. 215.4 sq. cm

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The hemisphere radius is 3 cm, so the cone height is 7 - 3 = 4 cm. The slant height of the cone is sqrt(3^2 + 4^2) = 5 cm. Total area = (2 * pi * r^2) + (pi * r * l) = (2 * pi * 9) + (pi * 3 * 5) = 18pi + 15pi = 33pi = 33 * 3.14 = 103.62. Option A is the closest.

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