Naomi is building a circuit board.The final microchip should have a surface area of 864 square millimeters. The height of the microchip can be a maximum of 4 millimeters. What are the maximum dimensions of the microchip she can use?
a. 8mm and 16 mm
b. 6mm and 12 mm
c. 9mm and 18 mm
d. 12mm and 24mm
