Answer:
The total surface area of this object is 510 cm^2.
Explanation:
Here L = 12 cm, W = 7 cm and H = 9 cm.
There are 2 panels 12 by 9 cm, 2 panels 12 by 7 cm, and 2 panels 7 by 9 cm. The combined areas are:
2(108 cm^2) + 2(84 cm^2) + 2( 63 cm^2) = 510 cm^2 total area