Question 132996
There are two possible situations:


{{{drawing(400,400,-1,5,-1,5,
red(triangle(0,0,0,sqrt(13),2,0)),
green(triangle(2.5,0,2.5,3,4.5,0)),
locate(-.4,sqrt(13)/2,sqrt(13)),
locate(1.4,sqrt(13)/2,a),
locate(1,-.1,2),
locate(3.5,-.1,2),
locate(2.3,1.5,a),
locate(3.9,1.5,sqrt(13))
)}}}


Either:
{{{a=sqrt((sqrt(13))^2+2^2)=sqrt(13+4)=sqrt(17)}}}, or



{{{a=sqrt((sqrt(13))^2-2^2)=sqrt(13-4)=sqrt(9)=3}}}