 Each level of play has different specifications for the size and shape of the key : in American leagues , where the basketball court is measured in imperial units , the shape is rectangular , while in FIBA @-@ sanctioned events , which use the metric system , the shape was trapezoidal , before being changed to a rectangle as well . In addition to the bounding rectangle , the key includes a free @-@ throw circle at its " head " or " top " . 
 Each level of play <a href='got' title='1'><mark>has</mark></a> different specifications for the size and shape of the key : in American leagues , where the basketball court is measured in imperial units , the shape is rectangular , while in FIBA @-@ sanctioned events , which use the metric system , the shape was trapezoidal , before being changed to a rectangle as well . In addition to the bounding rectangle , the key <a href='uninflect' title='2'><mark>includes</mark></a> a free @-@ throw circle at its " head " or " top " . 
Each level of play got diff specifications fir the size and shape of the key : in American leagues , where da basketball court is measured in imperial units , tdashape is rectangular , while in FIBA @-@ sanctioned events , which use the metric system , the shape was trapezoidal , b4 being changed to a rectangle as well . In addition to the bounding rectangle , the key include a free @-@ throw circle at its " head " or " top " .