SOLUTION: A semicircle is folded to form a right circular cone so that its original base which measures 5 cm becomes the circumference of the cone base. Find :-
a)The diameter of the base
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-> SOLUTION: A semicircle is folded to form a right circular cone so that its original base which measures 5 cm becomes the circumference of the cone base. Find :-
a)The diameter of the base
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Question 41448: A semicircle is folded to form a right circular cone so that its original base which measures 5 cm becomes the circumference of the cone base. Find :-
a)The diameter of the base
b)The curved surface area of the cone
This is what I have done
a)Diameter of the cone now = original base/2 = 5/2 = 2.5
b)Since the new diameter = 2.5 thus radius = diameter/2 = 2.5/2 = 1.25
Slant height = radius (is it correct ?)
Curved surface are of the cone
= PI r l (r = radius and l = slant length)
= 3.142 x 1.25 x 1.25
= 4.909375
= 4.9 Answer by venugopalramana(3286) (Show Source):
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A semicircle is folded to form a right circular cone so that its original base which measures 5 cm becomes the circumference of the cone base. Find :-
a)The diameter of the base
b)The curved surface area of the cone
This is what I have done
a)Diameter of the cone now = original base/2 = 5/2 = 2.5...NO..
CIRCUMFERENCE OF SEMICIRCLE =5 = CIRCUMFERENCE OF CONE BOTTOM=PI*DCONE
SO DCONE=5/PI....RCONE=5/2PI
L= SLANT HEIGHT OF CONE = RADIUS OF ORIGINAL SEMICIRCLE=5/PI...(PERIMETER OF SEMICIRCLE=PI*R)
CSA OF CONE=PI*R*L=PI*(5/2PI)*(5/PI)=25/2PI=3.98
b)Since the new diameter = 2.5 thus radius = diameter/2 = 2.5/2 = 1.25
Slant height = radius (is it correct ?)
Curved surface are of the cone
= PI r l (r = radius and l = slant length)
= 3.142 x 1.25 x 1.25
= 4.909375
= 4.9
