The surface area of a rectangular prism is the sum of the areas of its faces added together. From the picture, we can see that the prism is constructed of 4 faces that measure 7 cm by 9 cm and 2 faces that measure 7 cm by 7 cm.
The area of one 7 cm by 9 cm face is 63 cm². Together, all four of the faces add up to 252 cm².
The area of one 7 cm by 7 cm face is 49 cm². Together, the two faces add up to 98 cm².
Using these areas, we can say that the total surface area of the prism would be 252 cm² added to 98 cm², or 350 cm².