The key thing you want to remember is that with converting area from square inches to square cm, you have to use a square inches to square cm conversion, not an inches to cm conversion. This means that you must multiply by (2.5 cm/1 inch)^2, or 6.25 square cm/square in.
In your problem, you have 19 square inches:
19 square in. * 6.25 square cm/square in. = 118.75 square cm.
Thus 19 square inches = 118.75 square cm.
To help reinforce your understanding of these concepts, I've searched and found a webpage with the standard conversion of square inches to square centimeters, as well as a video tutorial that address problems similar to this one, and I thought they might be helpful to you. I've listed them below.
As always, if you need more help, please clarify where you are in the process and what's giving you trouble. I'd be more than happy to continue to assist.
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