Test: Symmetry - 1 - Class 4 MCQ

Symmetry in geometry refers to the balanced and proportionate similarity found in two halves of an object. It means that one-half is the mirror image of the other half.

The line along which a figure can be folded to obtain symmetrical halves is called the axis of symmetry. It divides the object into two mirror-image halves.

A rectangle is an example of an irregular shape with symmetry. It has two pairs of opposite sides that are equal, which results in symmetry.

1. Two shapes are exactly the same when moved, rotated, or flipped.

This means that a shape exhibits symmetry if there exists a transformation (such as a translation, rotation, or reflection) that maps the shape onto itself. In other words, the shape looks the same after undergoing the specified transformation.

Let's briefly review the other options to ensure clarity:

• 2. Two shapes have equal sides and angles: This describes congruence, not symmetry.
• 3. Two shapes have the same area: This describes similarity or equivalence of areas, not symmetry.
• 4. Two shapes have a common center: This describes concentricity, not symmetry.

Therefore, the correct answer regarding the definition of symmetry in mathematics is 1. Two shapes are exactly the same when moved, rotated, or flipped.

When an image looks identical to the original image after being turned or flipped, it is called rotational symmetry. The shape can be rotated by a certain angle and still maintain its original form.

A square has four lines of symmetry. It can be folded vertically, horizontally, and along both diagonals to obtain symmetrical halves.

Translation symmetry is characterized by sliding an object along an axis without changing its orientation. It is also known as sliding symmetry.

A circle has infinite lines of symmetry passing through its center. Any line passing through the center of a circle divides it into two symmetrical halves.

The order of symmetry for a shape that coincides with itself after a 180-degree rotation is 180 degrees. In other words, the shape looks the same after rotating it by 180 degrees.

A parallelogram possesses reflection symmetry. It can be divided into two congruent parts by a line of reflection.