Who is really good at math and would be willing to me with 3 questions? i'm on a time limit.

Cindy uses 1-inch cubes to find the volume of a jewelry box shaped like a rectangular prism. she uses 780 cubes to completely fill the jewelry box with no gaps or overlaps. if the jewelry box is 13 inches long and 5 inches wide, how tall is cindy’s jewelry box?

What describes horizontal cross section of the right rectangle 6m 8m 5m

With alll of except for the 2 that i did already