Final answer:
The corresponding angles theorem has been proved by using the Angle Addition Postulate and the fact that the angles ∠AGE and ∠CHE are congruent.
Step-by-step explanation:
To complete the proof, we can use the fact that segment AB is parallel to segment CD and points E, G, H, and F are collinear. Since segment AB is parallel to segment CD, the measure of ∠AGE plus the measure of ∠AGF must be equal to 180°, by the Angle Addition Postulate. We can substitute the measure of ∠EGF (which is 180°) in place of the measure of ∠AGE plus the measure of ∠AGF, resulting in the equation: the measure of ∠AGE plus the measure of ∠AGF equals 180°.
Using the same logic, we can also conclude that the measure of ∠CHE plus the measure of ∠AGF equals 180°. By substituting the measure of ∠EGF (which is 180°) for the measure of ∠CHE plus the measure of ∠AGF, we can say that the measure of ∠AGE plus the measure of ∠AGF equals the measure of ∠CHE plus the measure of ∠AGF.
Since both sides of the equation have the measure of ∠AGF, we can subtract it from both sides to get the measure of ∠AGE equals the measure of ∠CHE. Finally, since the angles have equal measures, we can use the definition of congruence to conclude that ∠AGE is congruent to ∠CHE.