As in right figure,in a quadrilateral ABCD,we have its diagonal AC bisects∠DAB,and AB=21,AD=9,BC=DC=10,then the distance
As in right figure,in a quadrilateral ABCD,we have its diagonal AC bisects∠DAB,and AB=21,AD=9,BC=DC=10,then the distance from point C to line AB is______,and the length of AC is______. (英漢詞典:quadrilateral 四邊形;bisect 平分)