Number of sides Shape Minimum number of triangles Sum of interior angles
3 Triangle 1 180
4 Quadrilateral 2 360
5 Pentagon 3 540
6 Hexagon 4 720
7 Heptagon 5 900
8 Octagon 6 1080
9 Nonagon 7 1260
10 Decagon 8 1440
3 Triangle 1 180
4 Quadrilateral 2 360
5 Pentagon 3 540
6 Hexagon 4 720
7 Heptagon 5 900
8 Octagon 6 1080
9 Nonagon 7 1260
10 Decagon 8 1440