Which of these is the best definition of a circle?

Which one is true about the hexagons ?

❤️ (geometry) does the construction demonstrate how to copy an angle correctly using technology a) yes; the distance between points a and f was used to create circle h b) yes; the distance between points f and g was used to create circle h c)no; the distance between points a and f was used to create circle h d) no; the distance between points f and g was used to create circle h

How do i i solve this equation? -18 = x/3 + 3