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Module 1. Mathematics

The surface area of a cone whose height is 10 cm and diameter is 8 cm is

  • 40pi cm2 .
  • 80pi cm2.
  • 120pi cm2 .

giovanni asking:

how?? the lateral surface of a cone??

Community Comments (3)

K
Klemis3000 Posts: 9 12.04.2018 / 09:23
Question is just bad. The real area is ~59pi cm2.
Looks like they forgot to take base area into account and also using height instead of slant height for curved area. Slant height is calculated using Pythagorean equation s^2=h^2+(d/2)^2. Total area = base area + curved area; base area = pi*(d/2)^2; curved area = s*(d/2)
D
dimky Posts: 511 12.04.2018 / 15:49
Yes, lateral.
E
Eddz25 Posts: 7 22.05.2025 / 02:56
answer is wrong, it should be 59 pi

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