# Basic geometry

ANGLES

TYPES OF ANGLES

• Acute angles
• Right angles
• Obtuse angles
• Straight angles
• Reflex angles
• 360 degrees
• When not to simplify angles larger than 360 degrees
• Complementary angles
• Supplementary angles
• Vertically opposite angles
• Describing angles

SOLVING FOR ANGLES IN A DIAGRAM

• Angle question

TRIANGLES

• Types of triangles
• Handy Hint #15 - Angles within a triangle rule

DESCRIBING TRIANGLES USING INTERIOR ANGLES

• Acute-angled triangles
• Right-angled triangles
• Obtuse-angled triangles

DESCRIBING TRIANGLES USING SIDES

• Equilateral triangles
• Isosceles triangles
• Scalene triangles

EXTERIOR ANGLES

• Triangle angles question

PARALLEL LINES

• Transversal lines
• Corresponding angles
• Alternate angles
• Co-interior angles
• Parallel lines question

ANGLES OF ELEVATION AND DEPRESSION

• Boat and lighthouse question
• Handy Hint #16 - Making angles clear in diagrams

SYMMETRY

• Multiple axes of symmetry
• Symmetry and letters
• Reflecting using x- and y-axes