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Jessica wants to dress up as a witch for a costume party. She is making her own costume. She wants a hat with a slant height of 14 inches and a base radius of 9 inches. What is the lateral area of her hat?

A) 396 in squared

B) 254 in squared

C) 198 in squared

D) 63 in squared

pwolfey  Nov 2, 2017

Best Answer 

 #1
avatar+5258 
+2

Her hat is a cone. If you "unfold" a cone, it makes a sector of a circle.

 

 

lateral area of cone  =  area of sector 

 

area of sector / area of circle  =  circumference of base / circumference of circle

 

area of sector / [pi * 142]  =  [2pi * 9] / [2pi * 14]

 

area of sector / [pi * 142]  =  9 / 14

 

area of sector  =  [pi * 142] * 9/14  =  126pi

 

≈  396  in2

hectictar  Nov 3, 2017
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1+0 Answers

 #1
avatar+5258 
+2
Best Answer

Her hat is a cone. If you "unfold" a cone, it makes a sector of a circle.

 

 

lateral area of cone  =  area of sector 

 

area of sector / area of circle  =  circumference of base / circumference of circle

 

area of sector / [pi * 142]  =  [2pi * 9] / [2pi * 14]

 

area of sector / [pi * 142]  =  9 / 14

 

area of sector  =  [pi * 142] * 9/14  =  126pi

 

≈  396  in2

hectictar  Nov 3, 2017

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