ok if GH line length is that 8.6 you do the following:
since OH and OG are radiuses they are equal, we have in the triangle two equal angles beside 82 means each angle is 49 degree, now use "sine law" sine 82 / GH (8.6) = sine 49 / OH, OH equal 6.55, this is the radius, theta = arc/radius, provided that theta is in radian, 82 degree in radians would be 1.43 something multiply that by 6.55 (radius) you get arc GH = 9.4, since GH and HJ arcs are congruent hj = 9.4, if the answer is wrong tell me to revise in case you have a guide answre
