We have the next information
x= the shortest side measure
y= the second side measure
y=x+100
z= the third side measures
z=x+700
We know also that the perimeter is 2900 ft
Therefore the equation for the perimeter of the triangle will be
[tex]P=x+y+z[/tex][tex]2900=x+x+100+x+700[/tex]we sum like terms
[tex]2900=3x+800[/tex]then we isolate the x
[tex]3x=2900-800[/tex][tex]3x=2100[/tex][tex]x=\frac{2100}{3}=700[/tex]therefore
x=700ft
y=700+100=800ft
z=700+700=1400ft
The lengths of the sides of the lote are 700 ,800, and 1400 ft,