Since ray GI bisects ∠FGH, we know that the ray is in the middle of the angle, since it is a bisector. That means that both angles have the same value. ∠FGI is equal to 51º. Since we know that both of the angles are the same value, that makes m∠IGH also equal to 51º. To find the angle of m∠FGH, we add both angles together to get our answer: 102º.
