Find the missing figure in the given pattern to replace the question mark (?):
$$\text{Triangle (3 sides) }\to \text{ Square (4 sides) }\to \text{ Pentagon (5 sides) }\to \text{ ?}$$

The pattern follows a logical progression based on the number of straight sides of the geometric polygons:
* First figure: Triangle = $3$ sides
* Second figure: Square = $4$ sides
* Third figure: Pentagon = $5$ sides

Following this increasing linear sequence ($+1$ side at each step), the next figure must have:

$$5+1=6\text{ sides}$$

A polygon with $6$ sides is a Hexagon.