The area of this polygon is 309 square meters. What is the length of the side labeled with a question mark? Enter your answer in the box. m Polygon in the shape of a letter L flipped vertically, which could be formed by a horizontal rectangle attached along the top part of a vertical rectangle. The top side of the figure is 16 m, the left side of the figure is 30 meters, the bottom side of the figure is 7 m, and the right side of the figure, which is the right side of the horizontal rectangle, is labeled with a question mark.