The lowest common denominator is 9/90 and 14/90, multiplying 1/10 by 9/9 and 7/45 by 2/2. I am assuming you know how to solve for LCD? If you don't I can explain in comments.
Answer:
A
Step-by-step explanation:
I'm pretty sure some smart guy in Greece noticed this but:
Since 4 + 8 = 12, thats the only option where 2 of the smaller sides add up to the big one. I don't know much of the reasoning behind this but my math teacher showed it to us by using Popsicle sticks to make triangles. You can try it if that helps you think about it. Apparently, if you add up the 2 smaller sides, then it HAS to be more than the biggest side.
