# Topics in Geometry ## Objects in geometry ### Points * [[vertex]] * [[vector]] ### Lines * [[line]] * [[gradient]] * [[perpendicular]] * [[perpendicular bisector]] * [[perpendicular distance]] * [[midpoint]] ### Shapes * [[shape]] * [[perimeter]] * [[perpendicular height]] * [[equation of a shape]] ### Triangles * [[triangle]] * [[equilateral triangle]] * [[isosceles triangle]] * [[right-angled triangle]] * [[scalene triangle]] * [[Heron's formula]] ### Quadrilaterals * [[quadrilateral]] * [[square]] * [[rectangle]] * [[rhombus]] * [[parallelogram]] * [[kite]] * [[dart]] * [[trapezium]] ### Regular Polygons * [[regular polygon]] * [[pentagon]] * [[hexagon]] ### Polygons * [[polygon]] * [[angles of a polygon]] * [[diagonal]] ### Circles * [[circle]] * [[chord]] * [[diameter]] * [[tangent]] * [[sector]] * [[concentric]] * [[circumcircle]] * [[in-circle]] * [[lune]] ## Angles ### Basic Angles * [[angle]] * [[right-angle]] * [[angles at a point]] * [[angles on a straight line]] * [[vertically opposite]] * [[supplementary angles]] * [[complementary angles]] ### Angles in Parallel Lines * [[angles and parallel lines]] ### Circle Theorems * [[angle in a semi-circle]] * [[angle between a radius and tangent]] * [[angle at the circumference is half that at the centre]] * [[angles in the same segment]] * [[cyclic quadrilateral]] * [[alternate segment theorem]] * [[intersecting chords theorem]] ### Trigonometry * [[trigonometry]] * [[cosine rule]] * [[sine rule]] * [[sine formula for the area of a triangle]] * [[compound angle formulae]] ## Lengths * [[Pythagoras]] * [[parallelogram identity]] * [[parallelogram law]] ## Areas * [[area]] * [[dissection]] ## Symmetries * [[symmetry]] * [[line of symmetry]] * [[transformation]] * [[congruent]] * [[similarity]] * [[bisection]] * [[tessellation]]