Question

find the number of sides of polygon,the sum of whose angle is (a) 1400 degree (b) 1080 degree​

Answer 1

Regular Polygons

A polygon is a plane (2D) shape with straight sides.

To be a regular polygon all the sides and angles must be the same:

2d triangle

Triangle - 3 Sides 2d square

Square - 4 Sides

2d pentagon

Pentagon - 5 Sides 2d hexagon

Hexagon - 6 sides

2d heptagon

Heptagon - 7 Sides 2d octagon

Octagon - 8 Sides

2d nonagon

Nonagon - 9 Sides 2d decagon

Decagon - 10 Sides

Other Common Polygons

These are 2D shapes, and they are polygons, but not regular polygons:

2d quadrilateral

Quadrilateral

Any 4 sided 2D shape 2d rectangle

Rectangle - 4 Sides

All right angles