Rotational and Line Symmetry Concepts

The video tutorial by Miss Backfish introduces the concepts of line and rotational symmetry, crucial in geometry and algebra. Line symmetry is defined as a line dividing a figure into two congruent parts that can be mapped onto each other by reflection. Various examples, including parallelograms and stars, illustrate line symmetry. Rotational symmetry is explained as a figure mapping onto itself by rotation of less than 360 degrees, with examples like triangles and stars. The video concludes with a summary of these symmetry concepts.

What is the definition of line symmetry?

• A figure can be divided into three parts.

• A figure has no symmetry.

• A figure can be rotated to look the same.

• A figure can be divided into two congruent parts by a line.

Which of the following shapes has a vertical line of symmetry?

• A lopsided star

• A perfectly symmetrical star

• A lopsided triangle

• A parallelogram

How many lines of symmetry does a five-pointed star have?

• Six

• Three

• Four

• Five

What is rotational symmetry?

• A figure can be divided into two congruent parts by a line.

• A figure can be divided into three parts.

• A figure can be rotated less than 360 degrees to look the same.

• A figure has no symmetry.

What is the order of rotational symmetry for a shape that looks the same after a 180-degree rotation?

• 1

• 2

• 3

• 4

How many positions does an equilateral triangle have where it looks the same when rotated?

• Five

• Four

• Three

• Two

What is the angle of rotational symmetry for a shape with an order of 4?

• 120 degrees

• 45 degrees

• 90 degrees

• 60 degrees

Which shape has no rotational symmetry?

• A lopsided triangle

• A six-pointed star

• A square

• A five-pointed star

How many lines of symmetry does a six-pointed star have?

• Seven

• Six

• Four

• Five

What is the angle of rotational symmetry for a five-pointed star?

• 90 degrees

• 72 degrees

• 60 degrees

• 120 degrees