Surface Area of a Right Circular Cone MCQs
Practice Surface Area of a Right Circular Cone multiple-choice questions from Surface Areas and Volumes (Class 9 Maths) - tap an answer for instant feedback and a step-by-step solution. Practice the full set free on the RankByte app.
Surface Area of a Right Circular ConeQuiz - Solve & Score
Q1. A right circular cone has base radius 7 cm and vertical height 24 cm (pi = 22/7). After finding its slant height, its curved surface area is?
- A.550 cm^2
- B.704 cm^2
- C.528 cm^2
- D.154 cm^2
Answer: A. 550 cm^2
Q2. A right circular cone has base radius 21 cm and vertical height 28 cm (pi = 22/7). After finding its slant height, its curved surface area is?
- A.2310 cm^2
- B.3696 cm^2
- C.1848 cm^2
- D.1386 cm^2
Answer: A. 2310 cm^2
Spot-the-setup - a typical math numerical. The data on the table: 21 cm, 28 cm. We are after finding its slant height, its curved surface area is?. Tool of choice - l = √.(r^2+h^2) = √.(21^2+28^2) = 35. Rearrange it for the unknown before substituting. Numbers in: l = √.(r^2+h^2) = √.(21^2+28^2) = 35 → CSA = π.rl = (22/7)×.21×.35 = 2310 cm^2. Lock in option A) 2310 cm^2. Trap-watch: option B) '3696 cm^2' doesn't hold - That is the total surface; the curved part excludes the base; option C) '1848 cm^2' doesn't hold - Use the slant height l, not the vertical height h, in πrl.
Q3. A right circular cone has base radius 35 cm and vertical height 12 cm (pi = 22/7). After finding its slant height, its curved surface area is?
- A.4070 cm^2
- B.7920 cm^2
- C.1320 cm^2
- D.3850 cm^2
Answer: A. 4070 cm^2
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