1. **State the problem:** We need to find possible dimensions for rectilinear shapes with given perimeters. 2. **Recall the perimeter formula:** For rectilinear shapes, the perimeter $P$ is the sum of all outer side lengths. 3. **Important rule:** Each shape's perimeter is fixed, so the sum of all outer sides must equal the given perimeter. 4. **Example for Shape A (Perimeter = 18 cm):** - Suppose the L-shape has sides $a$, $b$, $c$, $d$, $e$, and $f$. - The perimeter is $P = a + b + c + d + e + f = 18$. 5. **Choose some dimensions:** For example, let $a=3$, $b=2$, $c=1$, $d=4$, $e=3$, $f=5$. 6. **Check the sum:** $$3 + 2 + 1 + 4 + 3 + 5 = 18$$ 7. **Repeat for other shapes:** Assign side lengths so their sum equals the given perimeter. 8. **Note:** Multiple dimension sets are possible; the key is the sum of outer sides equals the perimeter. This approach applies to all shapes A to F with their respective perimeters.