Answer : Conditional
The statement " If a polygon has six sides, then it is a hexagon" is an example of a conditional sentence. A conditional sentence is a type of sentence that make use of conditional constructions and also conditional verbs. A conditional sentence is made up of a conditional clause and a consequence. Here are some of the examples of conditional sentences :
When it rains heavily, the road becomes slippery and wet.
I would by the most expensive car if I won ten billion pesos.