1. **State the problem:** We need to find the coordinates of the center, $C$, of a rectangle given its bottom-left corner at $(4, -3)$ and top-right corner at $(18, 11)$. 2. **Formula used:** The center (or midpoint) of a rectangle can be found by averaging the x-coordinates and the y-coordinates of opposite corners. The formula for the midpoint $C = (x_c, y_c)$ is: $$ x_c = \frac{x_1 + x_2}{2}, \quad y_c = \frac{y_1 + y_2}{2} $$ where $(x_1, y_1)$ and $(x_2, y_2)$ are the coordinates of opposite corners. 3. **Apply the formula:** $$ x_c = \frac{4 + 18}{2} = \frac{22}{2} = 11 $$ $$ y_c = \frac{-3 + 11}{2} = \frac{8}{2} = 4 $$ 4. **Interpretation:** The center $C$ of the rectangle is at the point $(11, 4)$. **Final answer:** $$ C = (11, 4) $$