
We have to use the formula:

So,

Also, it will be

Hope you could understand.
If you have any query, feel free to ask.
By comparing the perimeters, we can deduce the scaling factor:

The areas scale with the square of the scaling factor, so the new area is

Answer:
- Circle X with radius 2 cm.
- Either of two lines parallel to AB.
Step-by-step explanation:
1. The definition of a circle is all the points in a plane that are at some radius r from a given point (the circle center). That is what you have, with a radius of 2 cm.
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2. Parallel lines are the same distance apart everywhere. Each line will have two parallel lines at some given distance from it, one on each side. Here, the separation distance from AB is 1 cm, so your locus of points is the two lines parallel AB that are 1 cm from it on either side.