How do I calculate/determine the area of a hexagon and pentagon ?

I know that I would measure each object's side, and then tally the Perimeter via adding each side's measurements - But how do I calculate the Area (for example, a square is easy to calculate, because you simply multiply the measurement of two of its sides in order to determine the area of the square) ?

One way to do this is to divide the hexagon or pentagon into triangles, find the area of each triangle (1/2 base times height) and add them up. One problem: finding the lengths of the base and height of each triangle may be problematic for someone in elementary school - assuming the person has no trig skills. If you are given any additional information besides just the length of each side, such as the overall diameter of the hexagon, you could figure out the areas of these triangles without using trigonometry.

Have that one side length is 4 and one side length is 2.2 that is all that they have given me