Question 447083
Let x ft be the width of the garden.
Let x+7 ft be the length of the garden.
...
{{{(x)^2+(x+7)^2=13^2}}} ... Pythagorean theorem
{{{x^2+x^2+14x+49=169}}}
{{{2x^2+14x+49-169=0}}}
{{{2x^2+14x-120=0}}}
{{{2(x^2+7x-60)=0}}}
{{{x^2+7x-60=0}}}
*[invoke quadratic "x", 1, 7, -60 ]
x must be positive.
x=5
x+7=12
Therefore, the dimensions of the garden is  5 ft by 12 ft.