document.write( "Question 1136847: I am trying to figure out how the area of a right trapezoid and the shorter base was calculated. From a diagram, the longer base is 8cm. The shorter base is unknown. The height is 3 cm. The slant height is 5 cm. I do not know how the total area was calculated at 18cm (squared) and the shorter base was calculated at 4 cm. \n" ); document.write( "

Algebra.Com's Answer #754666 by ikleyn(52831) $\"\"$ $\"About$

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document.write( "1.  Make a sketch.\r\n" );
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document.write( "2.  Your trapezoid has ONLY ONE obtuse angle.\r\n" );
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document.write( "    From the vertex of this obtuse angle draw the height (the perpendicular) to the longer base.\r\n" );
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document.write( "3.  You will obtain a right angled triangle.\r\n" );
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document.write( "    Do you see it ?\r\n" );
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document.write( "    Its hypotenuse is 5 cm.\r\n" );
document.write( "    Its leg is 3 cm.\r\n" );
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document.write( "    Hence, its other leg is 4 cm (3-4-5 right angled triangle).\r\n" );
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document.write( "4.  Hence, the shorter base of the trapezoid is 8 - 4 = 4 centimeters.\r\n" );
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document.write( "    Is it clear so far ?\r\n" );
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document.write( "5.  To find the area of the trapezoid, use the basic formula\r\n" );
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document.write( "    Area of the trapezoid =  =  = 18 square centimeters.\r\n" );
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