Question 1054669
{{{drawing(400,400,-1.5,1.5, -1.5,1.5, 
locate(0.05,.1,O),
circle(0,0,1), triangle(0,1,.67010309,-.742268,-.67010309,-.742268),
locate(.4,.1,8), locate(-.52,.1,8), locate(0,-.75,D),
green(line(0,0,0,1), line(-.67010309,-.742268,0,0), line(.67010309,-.742268,0,0),line(0,0,0,-.742268)), 
locate(-.03,1.8,A),locate(-.74,-.74,B), locate(.72,-.72,C),
locate(.03,.5,5), locate(-.25,-.3,5), locate(.23,-.3,5),
locate(-.4,-.75,x), locate(.03,-.35,y))}}}
x^2 + y^2 = 25
x^2 + (5+y)^2 = 64
(25-y^2 ) + 25 + 10y + y^2 = 64
10y = 14
y = 1.4
x^2 + (1.4)^2 = 25
x = 4.8
length of 3rd side is 9.6 cm