1. An angle changes in size as it undergoes a dilation.
FALSE because an angle or triangle will stretch the lengths of sides while maintaining the same angular degrees
2. A line segment usually decreases in size under contraction.
TRUE because contraction is shortening (opposite of dilation)
3. There can only be one obtuse angle in a triangle.
TRUE because 180 Rule: if one is greater than 90, then other 2 have to sum (and therefore be less than) 90
4. If a figure is reflected across the x-axis it is congruent to the original figure.
TRUE, reflection does not change dimensional aspects, only mirrors the figure across x or y axis
5. A figure derived from a previous figure by rotation, translation or dilation will be congruent to the original figure.
FALSE, only because dilation (stretching) changes the dimensional aspects
