Final answer:
A frame size of 16 x 20 would have 36 united inches.
Step-by-step explanation:
A frame size of 16 x 20 means that the frame has a length of 16 inches and a width of 20 inches. To find the united inches, you add the length and width together. In this case, it would be 16 + 20 = 36 united inches.