A pentagon has actually 5 sides, and can be made indigenous three triangles, therefore you understand what ...

... Its inner angles add up come 3 × 180° = 540°

And when it is regular (all angles the same), climate each angle is 540° / 5 = 108°

(Exercise: make sure each triangle here adds up to 180°, and also check the the pentagon"s interior angles include up to 540°)

The inner Angles of a Pentagon include up to 540°

## The basic Rule

ShapeSidesSum ofInterior AnglesShapeEach Angle
 If that is a Regular Polygon (all sides space equal, all angles space equal) Triangle 3 180° 60° Quadrilateral 4 360° 90° Pentagon 5 540° 108° Hexagon 6 720° 120° Heptagon (or Septagon) 7 900° 128.57...° Octagon 8 1080° 135° Nonagon 9 1260° 140° ... ... .. ...See more: What Does The Name Hussein Mean ? Hussain Surname Meaning And Family History ... Any Polygon n (n−2) × 180° (n−2) × 180° / n

So the general ascendancy is:

Sum of inner Angles = (n−2) × 180°

Each edge (of a regular Polygon) = (n−2) × 180° / n

Perhaps an instance will help:

### Example: What about a regular Decagon (10 sides) ? Sum of inner Angles = (n−2) × 180°
= (10−2) × 180°
= 8 × 180°
= 1440°

And because that a continual Decagon:

Each internal angle = 1440°/10 = 144°

Note: inner Angles space sometimes referred to as "Internal Angles"

inner Angles Exterior Angles levels (Angle) 2D forms Triangles quadrilateral Geometry Index