Question 814212
The emphasis is on the rectangular bottom of the pool.  Depth is not relevant.

w for width, L for length.
wL is the area, so {{{wL=570}}} square meters.
Perimeter is {{{2w+2L=98}}} meters.
Two equations in two unknown variables.  Solve for one variable and substitute into the other equation and get the value for one variable...


as a start,
{{{w=570/L}}};
{{{2w+2L=98}}}
{{{2(570/L)+2L=98}}}
{{{2*570+2L^2=98L}}}
.
Can you continue this?