<PRE><B>Question 22256</B>
Let height= x
So length is x+7
Now apply Pythagorus Theorem
{{{(x+7)^2+x^2=13^2}}}
{{{2x^2+14x+49=169}}}subtract 169 from both sides to give
{{{2x^2+14x-120=0}}}take out the factor 2
{{{2(x^2+7x-60)=0}}} expression in brackets factors to
(x-5)(x+12)=0
so x=5 and x=-12
Obviously we want the positive x=5
So height of screen is 5 inches
and length is 5+7=12 inches 
Check:Use Pythagorus again
{{{5^2+12^2=13^2}}}
25 +144 =169 correct.
Hope this helps
Pete</PRE>