Question 3 - Figure it out - Page 238, 239 - Chapter 9 Class 6 - Symmetry (Ganita Prakash)

Transcript

Question 3 (a) Draw, wherever possible, a rough sketch of: A triangle with at least two lines of symmetry and at least two angles of symmetry.Equilateral Triangle It has 3 lines of symmetry Checking Rotational SymmetryRotational symmetry order of 3 ∴ Equilateral triangle is the required triangle Question 3 (b) Draw, wherever possible, a rough sketch of: A triangle with only one line of symmetry but not having rotational symmetry.Isosceles Triangle Number of Lines of symmetry = 1 Checking Rotational SymmetryFigure is same only after rotating 360° - one full round So, we say that this figure does not have rotational symmetry. ∴ Isosceles triangle is the required triangle Question 3 (c) Draw, wherever possible, a rough sketch of: A quadrilateral with rotational symmetry but no reflection symmetry.Parallelogram Number of Lines of symmetry = 1 Checking Rotational SymmetryFigure is same at 180° & 360° The figure is same as that of initial 2 times So, we say that figure has Rotational Symmetry of order 2 ∴ Parallelogram is the required quadrilateral Question 3 (d) Draw, wherever possible, a rough sketch of: A quadrilateral with reflection symmetry but not having rotational symmetry.Trapezium Number of Lines of symmetry = 1 Checking Rotational SymmetryFigure is same only after rotating 360° - one full round So, we say that this figure does not have rotational symmetry. ∴ Trapezium is the required quadrilateral