How would I find the measure of this angle?
To find the angle measure, you have to know some arc properties. The one we'll use is the Inscribed Angle Property, which states that an inscribed angle is half of its corresponding arc. In other words, angle GFH is half of 166 (the corresponding arc is GH, which measures 166). 166/2 is 83. We can then find the measure GHF by adding our found angle measures and subtracting them from 180. GHF=180-(67+83) GHF=180-150 GHF=30 degrees :)
I hope this helps you