Geometry

Study Notes

Geometry involves understanding shapes, their properties, and how they move or change position. It covers 2D shapes, angles, and transformations like reflection, rotation, and translation.

• 2D Shapes — shapes with two dimensions, such as width and height.
  Example: Equilateral triangle has 3 vertices, 3 edges, and 3 lines of symmetry.
• Right-Angled Triangle — a triangle with one angle equal to 90 degrees.
  Example: A triangle with one right angle.
• Isosceles Triangle — a triangle with two sides and two angles equal.
  Example: A triangle with 1 line of symmetry.
• Square — a regular quadrilateral with equal sides and angles.
  Example: A shape with 4 lines of symmetry.
• Rectangle — a quadrilateral with opposite sides equal and parallel.
  Example: A shape with 2 lines of symmetry.
• Rhombus — a quadrilateral with all sides equal and opposite angles equal.
  Example: A shape with 2 lines of symmetry.
• Trapezium — a quadrilateral with one pair of parallel lines.
  Example: A shape with 4 vertices and 4 edges.
• Circle — a shape with an infinite number of lines of symmetry.
  Example: A shape with a curved face and a 360-degree angle at the center.
• Reflection — a mirror image of a shape across a line.
  Example: A shape flipped over a line of reflection.
• Rotation — circular movement of an object around a center.
  Example: Rotating a shape by an angle around a point.
• Translation — moving a shape from one place to another without changing its size.
  Example: Shifting a shape up, down, left, or right.

Exam Tips

Key Definitions to Remember

• 2D Shapes: Shapes with two dimensions, such as width and height.
• Right-Angled Triangle: A triangle with one angle equal to 90 degrees.
• Reflection: A mirror image of a shape across a line.
• Rotation: Circular movement of an object around a center.
• Translation: Moving a shape from one place to another without changing its size.

Common Confusions

• Confusing the properties of different triangles, such as isosceles and scalene.
• Misunderstanding the difference between reflection and rotation.

Typical Exam Questions

• What is the sum of the interior angles of a triangle?
  180 degrees
• How many lines of symmetry does a square have?
  Four
• What is the definition of a reflection in geometry?
  A mirror image of a shape across a line.

What Examiners Usually Test

• Understanding of shape properties and symmetry.
• Ability to identify and describe transformations like reflection and rotation.
• Knowledge of angle properties in different shapes.