We can calculate the width of the rectangle patio with pythagorean theorem:
[tex]\begin{gathered} \text{Base of triangle=15-12=3} \\ c^2=a^2+b^2 \\ 5^2=3^2+b^2 \\ b=\sqrt[]{25-9} \\ b=\sqrt[]{16} \\ b=4 \end{gathered}[/tex]Then, she need to put trim on the edge of the floow of the patio that is wood planks and DOES NOT share and edge with the brick part:
[tex]\begin{gathered} T=12+4+12 \\ T=28\text{ feet} \end{gathered}[/tex]Loretta need to put 28 feet of trim.