Interior angle of regular polygon formula
- finding angles in polygons
- finding angles in polygons worksheet
- missing angles in polygons
- missing angles in polygons worksheet
Formula for interior angles of a polygon
Exterior angle formula...
Interior Angles of Polygons
An Interior Angle is an angle inside a shape:
Another example:
Triangles
The Interior Angles of a Triangle add up to 180°
90° + 60° + 30° = 180°
It works for this triangle
80° + 70° + 30° = 180°
It still works!
One angle went up by 10°,
and the other went down by 10°
Quadrilaterals (Squares, etc)
(A Quadrilateral has 4 straight sides)
Let's try a square:
90° + 90° + 90° + 90° = 360°
A Square adds up to 360°
Now tilt a line by 10°:
80° + 100° + 90° + 90° = 360°
It still adds up to 360°
The Interior Angles of a Quadrilateral add up to 360°
Because there are 2 triangles in a square ...
The interior angles in a triangle add up to 180° ...
...
and for the square they add up to 360° ...
... because the square can be made from two triangles!
Pentagon
A pentagon has 5 sides, and can be made from three triangles, so you know what ...
...
its interior angles add up to 3 × 180° = 540°
When the pentagon is regular (all angles equal), each angle is 540° /
- missing angles in polygons corbettmaths
- finding missing angles in polygons