document.write( "Question 975487: A lampshade in form of a frustum of a cone has the upper and lower diameters of 10cm and 20cm respectively and a height of 12cm. Calculate the area of the cloth required to cover the lampshade. \n" ); document.write( "

Algebra.Com's Answer #597244 by josgarithmetic(39617) $\"\"$ $\"About$

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Refer to your textbook or to this wikipedia article: https://en.wikipedia.org/wiki/Frustum .\r
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\n" ); document.write( "\n" ); document.write( "If s is slant height, h is the frustrum height, and R and r are the bigger and smaller radii, then you can form a right triangle from the frustrum with the Pythagorean Theorem equation $\"s%5E2=%28R-r%29%5E2%2Bh%5E2\"$
\n" ); document.write( "and
\n" ); document.write( "Surface Area of the frustrum is $\"pi%28R-r%29%2As\"$ .\r
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\n" ); document.write( "\n" ); document.write( "The problem description gives you enough information for R and r, and you can find s.\r
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\n" ); document.write( "\n" ); document.write( " $\"s=sqrt%28%28R-r%29%5E2%2Bh%5E2%29\"$
\n" ); document.write( "Surface Area is then $\"highlight_green%28pi%28R-r%29%2Asqrt%28%28R-r%29%5E2%2Bh%5E2%29%29\"$ .
\n" ); document.write( "Radii are each half of the given diameters.\r
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\n" ); document.write( "\n" ); document.write( " $\"highlight%28SurfacArea=pi%2810%2B5%29sqrt%28%2810-5%29%5E2%2B12%5E2%29%29\"$ ;
\n" ); document.write( "Compute the expression. \n" ); document.write( "

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