A sector is cut off from a circle radius 8.2cm to form a cone, if the radius of the resulting cone is 3.5cm, calculate the curved surface area of the cone. [take π = 22/7]
- A.
11.25cm^{2} - B.
12.83cm^{2} - C.
22.0cm^{2} - D.
67.2cm^{2} - E.
90.2cm^{2}
Correct Answer: Option E
Explanation
r = 3.5 cm; l = 8.2 cm.
Curved surface area = (pi rl)
= (frac{22}{7} times frac{7}{2} times frac{41}{5})
= 90.2 cm(^2)