A regular hexagon is comprised of six equilateral triangles. The "base" of each triangle is just 10 cm (in this case) and the "height" is sqrt(102 - 52).
Can you take it from here?
I understood the first part but Im confused at "is sqrt(10^2 - 5^2)". Is that the formula to solve?
sqrt(102 - 52) → sqrt(100 - 25) → sqrt(75) → 5*sqrt(3)
This is the height of the black(?) line going from the centre to the side in your picture.
So the two red lines and the black line make a triagnle that I solve the area for??? Sorry Im very confused now.