The area of △EBD is one third of the area of 3−4−5△ABC. Segment DE is perpendicular to segment AB. What is BD?[asy]
unitsize(10mm);
defaultpen(linewidth(.8pt)+fontsize(10pt));
dotfactor=4;
pair A=(0,0), B=(5,0), C=(1.8,2.4), D=(5-4sqrt(3)/3,0), E=(5-4sqrt(3)/3,sqrt(3));
pair[] ps={A,B,C,D,E};
draw(A--B--C--cycle);
draw(E--D);
draw(rightanglemark(E,D,B));
dot(ps);
label("A",A,SW);
label("B",B,SE);
label("C",C,N);
label("D",D,S);
label("E",E,NE);
label("3",midpoint(A--C),NW);
label("4",midpoint(C--B),NE);
label("5",midpoint(A--B),SW);[/asy]<spanclass=′latex−bold′>(A)</span>34<spanclass=′latex−bold′>(B)</span>5<spanclass=′latex−bold′>(C)</span>49<spanclass=′latex−bold′>(D)</span>343<spanclass=′latex−bold′>(E)</span>25