What is the measure of an exterior angle in a regular triangle?Write your answer as an integer or as a decimal rounded to the nearest tenth.

The measure of an exterior angle in a regular triangle (also known as an equilateral triangle) is 120 degrees.

Here's the step by step explanation:

1. A regular triangle has all its interior angles equal. The sum of the interior angles in a triangle is always 180 degrees.

2. Since a regular triangle has all its angles equal, each interior angle is 180/3 = 60 degrees.

3. An exterior angle of a triangle is formed when one side of the triangle is extended. It is the angle between the extended side and the adjacent side.

4. The exterior angle is supplementary to the interior angle (they add up to 180 degrees). So, the measure of the exterior angle is 180 - 60 = 120 degrees.