Match the volume of the cube to the length of each edge.

7

Step-by-step explanation:

If volume is equal to length to width to height, then 343 = l x w x h. Since the shape is a cube, all the sides are equal so length width and height are equal. Thus, they can all be represented by x. So 343 = x to the third power. You can then take 343 to the third root and get 7. Also, if I counted correctly, each individual unit cube on the length width and height are seven. So length is 7 width is 7 height is 7 and 343 to the third root is 7.