Interior angles

Interior Angles

• The term ‘interior angles’ typically refers to the angles formed on the inside of a shape.

Interior Angles of a Triangle

• In a triangle, the sum of the interior angles is always 180 degrees.
• This is true irrespective of the type of triangle – be it equilateral, isosceles, or scalene.

Interior Angles of a Quadrilateral

• In a quadrilateral, the sum of the interior angles always totals 360 degrees.
• This rule applies to all quadrilaterals, whether they are a square, rectangle, paralelogram, rhombus, kite or trapezium.

Interior Angles of a Polygon

• For any polygon with a number of sides ‘n’, the sum of the interior angles is given by the formula (n - 2) × 180 degrees.
• An ‘n’-sided polygon is known as an ‘n’-gon. For instance, a five-sided polygon is a pentagon and a six-sided polygon is a hexagon.

Annexe Angles

• Annexe (or consecutive) angles are interior angles of a polygon that share a common side.
• For instance, in a rectangle, any two angles that share a common side are annexe angles. For a rectangle, these are 90 degrees each.

Understanding Interior angles and how to calculate them forms a core part of mastering Geometry. Always remember the formulas and rules discussed, and keep practicing various problems to solidify your understanding.