Precalculus , I need help

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 is the area of a triangle with vertices at (-3 3) (-3,2) and (1,2)?

What else equals 42 and 30 for multiply