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The height of a right circular cone is 4cm. The radius of its base is…

The height of a right circular cone is 4cm. The radius of its base is 3cm. Find the curved surface area

  • A.
    (9pi cm^2)
  • B.
    (15pi cm^2)
  • C.
    (16pi cm^2)
  • D.
    (20pi cm^2)
Correct Answer: Option B
Explanation

Curved surface area or a cone (=pi rl)
from the information (l^2 = 4^2 + 3^2 = 16+9\
l = sqrt{25} = 5; ∴ C.S.Ahspace{1mm} = frac{22}{7}times 3 times 5\
Since frac{22}{7}=pi ∴ C.S.Ahspace{1mm} =hspace{1mm}15pi)

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