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The area of the curved surface of the cone generated by the ...

The area of the curved surface of the cone generated by the sector of a circle radius 6cm and arc length 22cm is (π = 227)

A.

58 sq.cm

B.

34 sq.cm

C.

132 sq.cm

D.

77 sq.cm

E.

66 sq.cm

Correct answer is E

Given: length of the arc AOB = 22cm ; L = 6cm

Curved surface area of cone = πrl

Length of an arc = θ360 x 2 πL

= 22cm

but length of an arc = circumference of the cone = 2π

where r is the radius of the cone circle

2πr = 22, r = 222πr

= 11 x 722

= 72

curved surface area = πrl

= 227 x 72 x 6

= 66 sq.cm