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A glass ornament in the shape of a cone is placed onto a horizontal table. The cone has a radius of 7cm and a vertical height of 24cm. The surface area of the glass, in cm squared, in terms of pi is what?

 Oct 29, 2014

Best Answer 

 #4
avatar+128090 
+10

The slant height of the cone is the hypoteneuse of a 7 - 24 - 25 right triangle

The "formula" for a cone's surface area is   SA = pi(R2 + R*L)  where R is the radius and L is the slant height

So we have

Sa = pi[72+(7)(25)] = pi [49 + 175] = 224pi

 

 Oct 29, 2014
 #1
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A pain to answer.

 Oct 29, 2014
 #2
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its 42pi cm^2

 Oct 29, 2014
 #3
avatar+23245 
+10

A formula for the surface area of a cone is:  SA  =  πr² + πr√(h² + r²)

Substituting:  SA  =  π(7)² + π(7)√( (24)² + (7)² )

                     SA  =  49π + 7π√( 576 + 49 )

                     SA  =  49π + 7π√(625)

                     SA  =  49π + 7x25π 

                     SA  =  49π + 175π 

                     SA  =  224π 

 Oct 29, 2014
 #4
avatar+128090 
+10
Best Answer

The slant height of the cone is the hypoteneuse of a 7 - 24 - 25 right triangle

The "formula" for a cone's surface area is   SA = pi(R2 + R*L)  where R is the radius and L is the slant height

So we have

Sa = pi[72+(7)(25)] = pi [49 + 175] = 224pi

 

CPhill Oct 29, 2014

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