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JAMB Mathematics 1982 Question 39

Question 39

Mensuration of Solids

The area of the curved surface of the cone generated by the sector of a circle radius 6cm and arc length 22cm (π = 22/7) is

  1. A.58sq.cm
  2. B.34sq.cm
  3. C.132sq. cm
  4. D.77sq.cm
  5. E.66sq.cm.
Show the answer and explanation

Answer: E (66sq.cm.)

Explanation

The curved surface of the cone is the sector itself: area = ½ × radius × arc = ½ × 6 × 22 = 66sq.cm.