All numbers that only have one and itself as factors are prime. Therefore, to tell if a number is prime simply find it's factors. If it has more than two factors than it is not a prime number.
Answer: Parallel lines are marked with "feathers". Notice how they appear assets: the lines with one feather are parallels, and the lines with two feathers are parallel. A "box" at the point of intersection indicates the lines are perpendicular.
I found this on the web, maybe it will help you. Sorry if you still don't understand.
Hello,
Please, see the attached file.
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