Question 971542
Let the width the "w"
L=4w
If the diagonal is 51,
using pythagoras theorem
d²=w²+L²
where d=diagonal of the       rectangle,
      w=width
      L=lenght
Please try to draw the rectangle for better understanding
  now,
   51²=w²+(4w)²
   2601=w²+16w²
   2601=17w²
   w²=153
   w=\/153
   w=12.4
Now,lenght L=4w
   but w=12.4
  L=4*12.4
L=49.6
The lenght of the rectangle is 49.6cm
 CHEERS
   Timnewman,...