Final answer:
The measure of angle FGH in the congruent figures ACBD and EFGH is 90 degrees, corresponding to option 3 as the correct answer.
Step-by-step explanation:
The question posed falls under the subject of Mathematics and is suitable for High School level students who are studying geometry. Specifically, this is a problem related to parallel lines and the angles formed by a transversal, which in this case would be line AC intersecting lines BD and EH at the points labeled B and F, respectively.
To find the measure of angle FGH, we must use the information given about the angles within the paper airplane figure. Since ACBD is congruent to EFGH, angle B (90 degrees) is congruent to angle F. This means that angle F is also 90 degrees, and therefore the measure of angle FGH is also 90 degrees.
Option 3 is the correct answer to the student's question.