One shape that has at least one line of symmetry is a rectangle. A rectangle has two lines of symmetry. Line symmetry,is also known as reflection symmetry.
Other examples of shapes that have at least one line of symmetry include a square, with four lines of symmetry, and an equilateral triangle, with three lines of symmetry.
When one half of an object is the reflection of the other half, the object is said to have line or reflection symmetry. A shape must possess at least one line of symmetry for it to be considered to have reflection symmetry. An object or figure that is indistinguishable from its transformed image is said to be mirror-symmetric.