( 1 )作射线AC,线段DC;
( 2 )作∠BAD的补角,并标上字母;
( 3 )用量角器量出∠BAC的度数,并求出它的余角的度数(精确到度);
( 4 )在图中求作一点P,使P点到A、B、C、D四点的距离和最短.