Answer: 9.77 cm
Explanation:
The volume of the box is length x width x height (V = l*w*h). The area of the lid of the box is the length x width (A = l*w). So, to find the height, you can change the equation to volume / (length x width) = height (V/(l*w) = h). Divide the volume by the area (420/43), to get the answer of 9.77 cm.