Students can go through AP 7th Class Maths Notes Chapter 12 Symmetry to understand and remember the concepts easily.
Class 7 Maths Chapter 12 Notes Symmetry
→ Symmetry is an important geometrical concept.
→ A figure has a line symmetry, if there is a line about which the figures may be folded so that the two parts of the figure will coincide.
Ex :
→ A polygon is a closed figure made of several line segments.
→ The polygon made up of the least number of line segments is the triangle.
→ A polygon is said to be regular if all its sides are of equal length and all its angles are of equal measure.
→ An equilateral triangle is a regular polygon of three sides.
→ Each angle of an equilateral triangle is 60°.
→ A square is also regular because all its sides are of equal length and each of its angles is a right angle 90°.
→ The diagonals of a square are perpendicular bisectors of one another.
→ A pentagon is regular, if its sides should have equal length.
→ The measure of each angle of a regular pentagon is 108°.
→ A regular hexagon has all its sides equal and each of its angles measures 120°.
→ Each regular polygon has as many lines of symmetry as it has sides.
