<PRE><B>Question 211905</B>
H=10
A=distance from ground to top of ladder
B=distance from corner to bottom of ladder
A^2+B^2=H^2
B=A-4
A^2+(A-4)^2=10^2
A^2+(A^2-8A+16)=100
2A^2-8A+16=100
2A^2-8A-84=0
A^2-4A-42=0
Use the quadratic formula
A=(4+/-sqrt(4^2-4(1)(-42))/2
A=(4+/-sqrt(184))/2
A=(4+2*sqrt(46))/2
A=2+sqrt(46)=8.78
B=-2+sqrt(46)=4.78</PRE>