If they are perpendicular, they form a right angle. For example, this is perpendicular:
I_
If likes are parallel, they run along each other, never meeting. For example, these two lines are parallel:
___
___
Hope this helps!
Solution
Step 1
Write the numbers:

Step 2
Arrange the numbers in ascending order of magnitude.
Answer: Greatest Common Factor is 3
Step-by-step explanation: