Recall that the circle is  degrees. It is also important to recall that an equilateral triangle is a triangle whose side lengths are equal and the angles are equal. When the triangle is inscribed in the circle three lines can be drawn from the vertex on each point to the midpoint of the opposite side. This results in the following image.

From here, calculate the central angle between two points of the triangle. Since the circle is  degrees and the triangle is divided into six equal sectors then each sector is  degrees. Now, there are two sectors between two points of the triangle. Therefore, the minimum angle rotation that can be done to result in the same triangle is  degrees.

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into  equal pieces that means that rotating one of the pieces can be done two different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into  equal pieces that means that rotating one of the pieces can be done 8 different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into 16 equal pieces that means that rotating one of the pieces can be done  different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into  equal pieces that means that rotating one of the pieces can be done  different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into  equal pieces that means that rotating one of the pieces can be done  different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into  equal pieces that means that rotating one of the pieces can be done  different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

To calculate the number of symmetrical rotations, take one piece and rotate it clockwise until, it results in the exact image as originally started with. Since the circle is divided into  equal pieces that means that rotating one of the pieces can be done  different times and still keep rotational symmetry, which also means keeping the angles of each piece the same and returning to the original image.

Therefore the correct answer is .

Recall that a rigid motion is that that preserves the distances while undergoing a motion in the plane. This is also called an isometry, rigid transformations, or congruence transformations and there are four different types. Therefore, for the translation to be considered "rigid" the two figures must be congruent by definition of a rigid motion.

Therefore, the statement, "For a translation to be considered rigid, the starting and ending figures must be congruent." is true.

Recall that a rigid motion is that that preserves the distances while undergoing a motion in the plane. This is also called an isometry, rigid transformations, or congruence transformations and there are four different types.

These basic type of rigid motions include the following:

1. Rotation
2. Reflection
3. Translation
4. Glide Reflection

Therefore, of the answer selections, "Expansion" is the term that is NOT a rigid motion.