Symmetry is quite a common term used in day to day life. When we see certain figures with evenly balanced proportions, we say, “They are symmetrical”.
Take a piece of paper. Fold it in half. Spill a few drops of ink on one half side. Now press the halves together.
One of the two set-squares in your instrument box has angles of measure 30°, 60°, 90°.
Take two such identical set-squares.
How many lines of symmetry does the shape have?
Look yourself into a mirror