The Polygon has 5 sides hence it is called a Pentagon.
Note : if it is 4 sided, it could be a square, or rectangle or parallelogram or rhombus.
5 sided is a Pentagon
6 sided is an Hexagon
7 sided is a Heptagon
8 sided is an Octagon
9 sided is a Nonagon
10 sided is a Decagon
The one in the question is 5 sided, so it is a Pentagon.
