Question 805169
If the 70-foot long wall of the building is one side of the rectangular playground
and the adjacent sides are {{{x}}} feet long, we need
{{{x+70+x}}} feet of fencing.
 
Our equation is
{{{x+70+x=340}}}
{{{2x+70=340}}}
{{{2x=340-70}}}
{{{2x=270}}}
{{{x=270/2}}}
{{{highlight(x=135)}}}
The playground will be {{{highlight(135)}}} feet long.