1. **State the problem:** We want to find the perimeter of a quadrilateral formed by two scalene triangles. We only know two sides of one triangle and one side of the other. 2. **Understand the perimeter:** The perimeter of a quadrilateral is the sum of the lengths of all its four sides. 3. **Key insight:** Since the quadrilateral is formed by two triangles sharing a common side, the total perimeter is the sum of all unique sides of both triangles. 4. **Known sides:** Let the first triangle have sides $a$, $b$, and $c$, and the second triangle have sides $d$, $e$, and $f$. We know two sides of the first triangle, say $a$ and $b$, and one side of the second triangle, say $d$. 5. **Shared side:** The two triangles share one side, so one side length is common, say $c = d$. 6. **Perimeter formula:** The quadrilateral perimeter $P$ is the sum of the four unique sides: $$P = a + b + e + f$$ 7. **Problem:** We only know $a$, $b$, and $d$ (which equals $c$), but not $e$ and $f$. 8. **Conclusion:** Without knowing the other two sides $e$ and $f$ of the second triangle, or additional information (like angles or the length of the shared side), we cannot find the exact perimeter. 9. **Summary:** To find the perimeter, you need all four side lengths of the quadrilateral. Knowing only two sides of one triangle and one side of the other is insufficient. If you can find or measure the missing sides, then add all four unique sides to get the perimeter. **Final answer:** The perimeter equals the sum of all four unique sides of the quadrilateral, but with the given information, it cannot be determined.