Given that line segment, GC bisects ∠FGH
I made a sketch of the angles, they are not at scale.
That segment GC is an angle bisector indicates that it divides ∠FGH into halves. To determine the measure of the ∠FGC and ∠CGH you have to divide the measure of FGH by 2.
[tex]\angle\text{FGC}=\angle\text{CGH}=\frac{\angle\text{FGH}}{2}[/tex]
a) ∠FGH=86º
[tex]\begin{gathered} \angle\text{FGC}=\frac{\angle FGH}{2} \\ \angle\text{FGC}=\frac{86º}{2} \\ \angle\text{FGC}=43º \end{gathered}[/tex]
So, in this case, the measure of ∠FGC is 43º.
b) For this item you have to determine the measure of ∠FGH given that the measure of one of the angles determined by the bisector is ∠CGH. To determine the measure of ∠FGH you have to multiply ∠CGH by 2
[tex]\begin{gathered} \angle\text{FGH}=2\cdot\angle\text{CGH} \\ \angle\text{FGH}=2\cdot28º \\ \angle\text{FGH}=56º \end{gathered}[/tex]
