document.write( "Question 193049: what is the area of a regular hexagon whose sides are each 12 inches long. Round to the nearest squre inch. I drew the figure. used this formula: A=4 + 2, A=6. Or should it be 360 \n" ); document.write( "
Algebra.Com's Answer #144897 by RAY100(1637)![]() ![]() ![]() You can put this solution on YOUR website! good start,,somewhat complex solution,,your geometry book probably has a good ref\r \n" ); document.write( "\n" ); document.write( "lets start with the sketch,,,regular hexagon has 6 equal sides,12 for this problem. \n" ); document.write( "If we find the center of the hexagon, and then draw lines to each vertex, we have 6 identical triangles.\r \n" ); document.write( "\n" ); document.write( "Area of a triangle =1/2 base * height \n" ); document.write( "ok, but we only know base, we need to find height\r \n" ); document.write( "\n" ); document.write( "We also know the central angle,,,,,remember sum of angles of polygon =(n-2)(180) \n" ); document.write( "in our case (6-2)(180)=720,,,,,with 6 angles,,,720/6=120,,,(central angle of triangle).\r \n" ); document.write( "\n" ); document.write( "note the 120 deg on one triangle. \n" ); document.write( "also , please, draw an altitude on that triangle, from center to base. \n" ); document.write( "this is the height of that triangle. \n" ); document.write( "Note the altitude bisects the 120 angle into 2 equal 60 deg angles. \n" ); document.write( "we are almost there, \n" ); document.write( "in our triangle we have the 60 degree angle at the center vertex, 90 deg where altitude intersects the base, therefore the other vertex angle is 30 degrees,,,(sum of triangle =180 degrees)\r \n" ); document.write( "\n" ); document.write( "lets mark the 30 degree vertex, and the 90 degree angle.\r \n" ); document.write( "\n" ); document.write( "we now have a 30-60-90 degree triangle, with one side (opposite the 60 angle) equal to 6 \n" ); document.write( "which is half of the full side 12.\r \n" ); document.write( "\n" ); document.write( "we know from typical triangles that a 30-60-90 has sides of 1,2,sqrt3. \n" ); document.write( "in our case we need height,h, which is opposite the 30 deg angle. \n" ); document.write( "if the height is proportional to (1), hyp is (2), and the base side (sqrt3),,,but base side is 6\r \n" ); document.write( "\n" ); document.write( "sqrt3/6=1/h \n" ); document.write( "cross multiply,, \n" ); document.write( "(sqrt3)(h)=6 \n" ); document.write( "h=6/sqrt3=3.464\r \n" ); document.write( "\n" ); document.write( "now,,,area of triangle is 1/2 (base) (height) = 1/2 (12)(3.464)=20.78,,,,(full base=12)\r \n" ); document.write( "\n" ); document.write( "and remember we have 6 triangles in hexagon \n" ); document.write( "area if hexagon=6(20.78)=124.7=125\r \n" ); document.write( "\n" ); document.write( "this is generalized to Area of any polygon =1/2 (perimeter)(apothem) \n" ); document.write( "in our case,,,per =6*size of side, apothem is height \n" ); document.write( "Area=1/2 *(12*6)*3.464= 125 ok\r \n" ); document.write( "\n" ); document.write( "note, apothem is denoted (a), and is usually given,,just remember 1/2 * per*apothem \n" ); document.write( " |