ICSE Class 6 Maths, Unit 4: Geometry

What this unit aims at

Children in this class should be now in Van Heile’s level 2 of geometry learning i.e. Properties are perceived at Level 2, but they are isolated and unrelated. At Level 2 children would say "I know it's a rectangle because it is closed; it has 4 sides and 4 right angles; opposite sides are parallel; opposite sides are congruent; diagonals bisect each other; adjacent sides are perpendicular; etc...." All the properties known are listed since the student doesn't perceive any relationship between the properties, e.g., one implies the other. There is no knowledge of necessary and sufficient conditions. Like wise children develop their understanding about properties of other shapes and figure in this class.

Your child should be able to

• differentiate between different geometrical figures on the basis of their observable properties
• classify angle into different types on the basis of their measurement
• understand the difference between different types of triangles and the basis on which they are classified
• classify quadrilaterals as trapezium, parallelogram, rectangle, square, rhombus
• classify angles in different groups/types
• draw different types of triangles and quadrilaterals
• attempt to prepare solids using their nets
• observe the objects and tries to make strategies to decide about the symmetry of the object
• observe the reflection of objects in mirror and then tries to formulate rules about the symmetry of the object
• try to see the logic behind drawing an angle of certain measure using geometrical properties

Key concepts in this unit

• Basic geometrical ideas (2 -D): Introduction to geometry. Its linkage with and reflection in everyday experiences.
• Line, line segment, ray.
• Open and closed figures.
• Interior and exterior of closed figures.
• Curvilinear and linear boundaries
• Angle — Vertex, arm, interior and exterior.
• Triangle — vertices, sides, angles, interior and exterior, altitude and median.
• Quadrilateral — Sides, vertices, angles, diagonals, adjacent sides and opposite sides (only convex quadrilateral are to be discussed), interior and exterior of a quadrilateral.
• Circle — Centre, radius, diameter, arc, sector, chord, segment, semicircle, circumference, interior and exterior.
• Understanding Elementary Shapes (2-D and 3-D):
• Measure of Line segment.
• Measure of angles.
• Pair of lines – Intersecting and perpendicular lines, Parallel lines.
• Types of angles- acute, obtuse, right, straight, reflex, complete and zero angle.
• Classification of triangles (on the basis of sides, and of angles).
• Types of quadrilaterals – Trapezium, parallelogram, rectangle, square, rhombus.
• Simple polygons (introduction)
• (Upto octagons regulars as well as non-regular).
• Identification of 3-D shapes:
• Cubes, Cuboids, cylinder, sphere, cone, prism (triangular and square), pyramid (triangular and square), Identification and locating in the surroundings.
• Elements of 3-D figures. (Faces, Edges and vertices).
• Nets for cube, cuboids, cylinders, cones and tetrahedrons.
• Symmetry: (reflection)
• Observation and identification of 2-D symmetrical objects for reflection symmetry.
• Operation of reflection (taking mirror images) of simple 2-D objects.
• Recognising reflection symmetry (identifying axes).
• Constructions (using Straight edge Scale, protractor, compasses)
• Drawing of a line segment.
• Perpendicular bisector.
• Construction of angles (using protractor).
• Angle 60°, 120° (Using Compasses)
• Angle bisector- making angles of 30°, 45°, 90° etc. (using compasses).
• Angle equal to a given angle (using compass.)
• Drawing a line perpendicular to a given line from a point a) on the line b) outside the line.
• Construction of circle.