12.2.1 Symmetry

Question 1

figure has symmetry

Answer 1

if there is a transformation of the figure such that the image coincides with the preimage

Question 2

figure has line symmetry (or reflection symmetry)

Answer 2

if it can be reflected across a line so that the image coincides with
the preimage

Question 3

line of symmetry

Answer 3

(also called the axis of symmetry) divides the figure into two congruent halves

Question 4

figure has rotational symmetry (or radial symmetry)

Answer 4

if it can be rotated about a point by an angle greater than 0° and less than 360° so that the image coincides with the preimage

Question 5

three-dimensional figure has plane symmetry

Answer 5

if a plane can divide the figure into two congruent reflected halves

Question 6

three-dimensional figure has symmetry about an axis

Answer 6

if there is a line about which the figure can be rotated by an angle greater than 0° and less than 360° so that the image coincides with the preimage