Bookmark and Share

Symmetry

In this topic, we learn to identify line symmetry and rotational symmetry.

Topic: Identify Lines of Symmetry

  • A figure has line symmetry if it can be folded or reflected so that the two parts of the figure match

  • Even if two figures are congruent, they may not be symmetrical. They will be symmetrical only if the two parts of the figure match after being folded or reflected

  • The line of reflection is called the line of symmetry

  • Irregular figures do not have a line of symmetry

Topic: Name Symmetrical Quadrilaterals

  • A figure has line symmetry if it can be folded or reflected so that the two parts of the figure match

  • The line of reflection is called the line of symmetry

  • A quadrilateral is a plane figure with four sides and four angles. Parallelogram, square, rectangle, rhombus, and a trapezoid are special types of quadrilaterals

  • A rectangle has two lines of symmetry perpendicular to the sides. A square has four lines of symmetry

  • A trapezoid with two right angles has no line of symmetry. A rhombus has two lines of symmetry through opposite vertices

Topic: Rotational Symmetry

  • All figures, when rotated by 360° (or a full turn), will look exactly the same as they did before being turned

  • Some figures will look the same at certain angles of rotation which are less than 360° (90°, 180°, 270°). Such figures have rotational symmetry
    For example, the figure of a square reappears in the same position as it is turned 90°, 180°, 270° and 360°

Other Resources
View all concepts
Smartest Way to Practice Math
TenMarks is the smartest way to practice and learn math online. Experience our interactive worksheets that engage students.
Personalized program, mapped to state standards
Interactive worksheets with hints and video lessons
Rewards and certificates motivate students
Only $10 a month
TenMarks - Experience