Multiply both sides by 4
subtract 24r from both sides
simplify r - 24r to -23r
divide both sides by -23
two negatives make a positive
simplify 14/5/23 to 14/5 x 23
simplify 5 x 23 to 115
switch sides
Answer: r = 14/115.
I am guessing it is b! because BG and BA are sides, and BAU and BGN are angles.