Please help me with this

What is the volume of a rectangular prism if the length is 10.4 mm the width is 5 mm in the height is 8 mm

While scuba diving, rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. what expression can be used to find rajeev's new position? 12.6 – 8.7 –12.6 – 8.7 –12.6 – (–8.7) 12.6 – (–8.7)

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?