Is one side of a rectangular fish tank best represented by a point, line, plane, or ray?

Based on what i know about mean, this doesn't add up.

To describe a sequence of transformations that maps triangle abc onto triangle a"b"c", a student starts with a reflection over the x-axis.how should the student complete the sequence of transformations to map triangle abc onto triangle a"b"c"? plz

What is the circumference of a circle with an area of 50.24 cm²?