①以点B为圆心,以适当长为半径作弧,交AB于点N.交BC于点M;
②再分别以点M和点N为圆心,大于 MN的长为半径作弧,两弧交于点G;
③作射线BG交AD于F;
④过点A作AE⊥BF交BF于点P,交BC于点E;
⑤连接EF,PD.