126
Symmetry
Textbook Part 4, pp. 32–33
GoalUnderstand that a line of symmetry splits a shape into two matching (mirror-image) halves.
New words
symmetry · simmetriyaline of symmetry · simmetriya o‘qimirror · ko‘zgu
Explanation
A line that splits a shape into two matching halves is a line of symmetry. If you fold the shape along that line, the two halves fit exactly on top of each other. Butterflies, leaves, snowflakes and many buildings are symmetric.
Worked examples
The fronts of the madrasas on Registan Square are almost symmetric.
Symmetric letters: A, M, O, T, X, H, V.
Class activity
Ink butterfly: drop paint on one half of a sheet, fold it down the middle and open it. A symmetric “butterfly” appears. Children draw in the line of symmetry.
Practice
1
Aziza drew 35 symmetric shapes and Madina 14 fewer. How many in all?
56
2
Which letter is symmetric: F or A?
A
3
Is a human face roughly symmetric?
Yes, about a vertical line
4
Which directions can a line of symmetry go?
Vertical, horizontal or diagonal