Question 930301
SAS because
side AB in triangle ABC is congruent to side BD in triangle DBC;
side BC (in both triangles) is congruent with itself, 
and between those sides are congruent right angles ABD and DBC .
{{{drawing(300,300,-5,5,-2,8,
green(triangle(0,0,4.5,0,0,7)),
green(triangle(0,0,0,7,-4.5,0)),
line(-4.5,0,4.5,0),line(0,-2,0,8),
rectangle(-.2,0,.2,.2),locate(0.1,7.4,C),circle(0,7,0.05),
locate(-4.6,-0.05,A),locate(4.4,-0.05,D),locate(0.1,-.05,B)
)}}}