Let
x--------> the measure of the adjacent interior angle
y--------> the measure of an exterior angle at the vertex of a polygon
we know that
The measure of the adjacent interior angle and the measure of an exterior angle at the vertex of a polygon are supplementary angles
so
°
Examples
case 1)
In a square
°
so
°

In this case
The measure of an exterior angle at the vertex of a polygon equals the measure of the adjacent interior angle
case 2)
an equilateral triangle
°
so
°

In this case
The measure of an exterior angle at the vertex of a polygon is not equals the measure of the adjacent interior angle
therefore
the answer is
sometimes