## Elementary Geometry for College Students (7th Edition)

r=$\frac{20\sqrt 3}{3}$ s=$\frac{20\sqrt 3}{3}$
The radius and side of a regular hexagon are congruent. the apothem is the altitude of an equilateral triangle formed by its two surrounding radii and connected side. Therefore the apothem is the long leg of a 30 60 90 triangle with a radius for a hypotenuse. a=.5s$\sqrt 3$ 20=s$\sqrt 3$ s=$\frac{20\sqrt 3}{3}$ r=s=$\frac{20\sqrt 3}{3}$