As shown in the figure, in the quadrilateral ABCD, the angle B = 90 ° AC ⊥ DC, ab = 1cm, BC = DC = 2cm, then ad=_____ cm

As shown in the figure, in the quadrilateral ABCD, the angle B = 90 ° AC ⊥ DC, ab = 1cm, BC = DC = 2cm, then ad=_____ cm

In the quadrilateral ABCD, the angle B = 90 ° AC ⊥ DC
,AB=1cm BC=DC=2cm
Then ad=__ 3___ cm