Final answer:
The measure of an angle's adjacent exterior angle to a 40-degree interior angle in a triangle is 140 degrees.
Step-by-step explanation:
The question is asking for the measure of an adjacent exterior angle to a 40-degree interior angle of a triangle. By the definition of adjacent angles and the properties of a straight line, we can deduce that the adjacent exterior angle must add up to 180 degrees when combined with the interior angle because they form a linear pair. Therefore, to find the exterior angle, we subtract 40 degrees from 180 degrees:
- 180 degrees (straight line) - 40 degrees (interior angle) = 140 degrees (adjacent exterior angle).
Thus, the measure of the angle's adjacent exterior angle is 140 degrees.