Decide whether the hexagon is regular or irregular. Regular hexagons are defined as a hexagon with six equal sides. For a regular hexagon, knowing one measurement leads easily to knowing all the other measurements. For an irregular hexagon, each side, radius and apothem might be a different length. This requires a great many numbers to be identified before beginning to make calculations.
For a regular hexagon, there are six equilateral triangles inside it, with each side being the base of each triangle. For complex irregular hexagons, more creativity is required. Carefully identify shapes you can measure and of which you are able to calculate the area. Some hexagons may even require subtracting the area of a shape from the total.
For each polygon comprising the hexagon, calculate its area using any appropriate method. Add the areas of each polygon shape together to find the area of the entire hexagon.
Remember that area is always expressed in square units. For example, if the sides and other measurements of the hexagon are expressed in inches, then the area is expressed in square inches, or inches squared.