I don't know if this helps but the slope is -6/4
You need to use the cosine for this and this is how you do it.
We can calculate the width of the rectangle patio with pythagorean theorem:
![\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}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20%5Ctext%7BBase%20of%20triangle%3D15-12%3D3%7D%20%5C%5C%20c%5E2%3Da%5E2%2Bb%5E2%20%5C%5C%205%5E2%3D3%5E2%2Bb%5E2%20%5C%5C%20b%3D%5Csqrt%5B%5D%7B25-9%7D%20%5C%5C%20b%3D%5Csqrt%5B%5D%7B16%7D%20%5C%5C%20b%3D4%20%5Cend%7Bgathered%7D)
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:

Loretta need to put 28 feet of trim.
Set up a table of values and plug in those values to the x and then graph the points you came up with