Answer:
50 degrees
Explanation:
Theorem: The angle subtended by the diameter is a right angle.
By the Circle Theorem above, the angle at F is a right angle and thus Triangle EGF is a Right Triangle.
We are to determine the measure of GF.
|GE|=|GO|+|OE|=10+10=20 Inch
Using Trigonometry in the second triangle attached
![\sin E=(8.5)/(20) \\\angle E=\arcsin (8.5)/(20)\\\\\angle E=25^\circ$ (to the nearest degree)](https://img.qammunity.org/2021/formulas/mathematics/college/cul6at23eiunkx63350veasgxxh8rgs7ip.png)
Theorem: Angle at the centre is twice the angle at the circumference.
By the theorem above:
Measure of Arc GF = 2 X
![\angle FEG](https://img.qammunity.org/2021/formulas/mathematics/college/n13anxu83xbfmclt6h7g44g0toom81v6wq.png)
=2 X 25
mGF=50 degrees
Therefore, the measure of GF is 50 degrees (to the nearest degree)