+0

# slant height

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704
1
+252

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

Nov 2, 2017

#1
+7348
+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

Nov 3, 2017

#1
+7348
+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