Multiple choice

The total surface area of a right circular cone is 330 cm2. If the radius of its base is 7 cm, then find its slant height.

  1. 10 cm

  2. 15 cm

  3. 9 cm

  4. 8 cm
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D Correct answer
Explanation

Total surface area of a cone = pi*r*(r+l) = 330. 330 = (22/7)7(7+l) = 22*(7+l). 15 = 7+l. l = 8 cm.

AI explanation

The total surface area of a right circular cone is given by the formula pi times r times (r + l), where r is the radius and l is the slant height. Substituting the given values into the formula, we get 22/7 times 7 times (7 + l) equals 330. Simplifying the left side gives 22 times (7 + l), so 7 + l equals 330 divided by 22, which is 15. Therefore, the slant height l is 15 minus 7, resulting in 8 cm.

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