1. **State the problem:** We need to find the surface area of a cuboid with length $9$ m, width $12$ m, and height $4$ m. 2. **Formula for surface area of a cuboid:** $$\text{Surface Area} = 2(lw + lh + wh)$$ where $l$ is length, $w$ is width, and $h$ is height. 3. **Substitute the given values:** $$2(9 \times 12 + 9 \times 4 + 12 \times 4)$$ 4. **Calculate each product:** $$2(108 + 36 + 48)$$ 5. **Sum inside the parentheses:** $$2(\cancel{108 + 36 + 48}^{192})$$ 6. **Multiply by 2:** $$2 \times 192 = 384$$ 7. **Final answer:** The surface area of the cuboid is $384$ square meters.