document.write( "Question 1073352: 4 semicircle and 4 quadrant each of radius 7cm were cut off from a rectangular cardboard if perimeter 128cm.Find the perimeter of the cut cardboard. \n" ); document.write( "
Algebra.Com's Answer #688187 by KMST(5328)![]() ![]() You can put this solution on YOUR website! Without more detail, some assumptions need to be made. \n" ); document.write( " \n" ); document.write( "1) For starters, we need a conveniently shaped rectangle, \n" ); document.write( "with enough usable surface area, such as a 16 cm by 48 cm rectangle. \n" ); document.write( "Not all rectangles with a perimeter of 128 cm will yield \n" ); document.write( "4 semicircles and 4 quadrants each of radius 7cm. \n" ); document.write( "For example, a rectangle of with 8 cm and length 56 cm has a perimeter of \n" ); document.write( " \n" ); document.write( "but it cannot yield 4 semicircles and 4 quadrants each of radius 7cm, \n" ); document.write( "not even reshaping the cutouts to make circular sectors out of the wasted cutout pieces. \n" ); document.write( "That rectangle has an area of \n" ); document.write( " \n" ); document.write( "while 4 semicircles and 4 quadrants each of radius 7cm \n" ); document.write( "add to a larger total surface area. \n" ); document.write( "They have the same total area as the 3 circles of radius 7cm they would form, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "2) Then, there is the issue of where to cut from. \n" ); document.write( "One practical way, would be to cut the quadrants from the corners, \n" ); document.write( "and the semicircles along the long edges of the rectangle, \n" ); document.write( "with the straight sector edges along the sides of the rectangle, \n" ); document.write( "like this: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "With the assumptions above about \n" ); document.write( "1) the shape of the rectangle, and \n" ); document.write( "2) the way the circular sectors were cut off, \n" ); document.write( "we are left with a piece that has for perimeter \n" ); document.write( "some segments of the rectangle's straight edges, and \n" ); document.write( "the curved edges of 3 circles. \n" ); document.write( "The curved edges of 3 circles add up to \n" ); document.write( " \n" ); document.write( "For each circular sector piece cut off, \n" ); document.write( "the removed segment(s) of the rectangle's edges were \n" ); document.write( " \n" ); document.write( "So what's left as straight segments of the rectangle's original perimeter is \n" ); document.write( " \n" ); document.write( "So the straight plus curved parts of the perimeter of the \n" ); document.write( "piece leftoever of the rectangle is approximately \n" ); document.write( " \n" ); document.write( "If an exact expression is required, it would be \n" ); document.write( " |