Find the missing angle.

To find the missing angle, we'll assume that the two given angles are part of a triangle or that they are related to a linear pair.

If they are part of a triangle, the sum of the angles in a triangle is 180°.

So, the missing angle \( x \) can be calculated as follows:

\[
x = 180° - (15° + 85°)
\]
\[
x = 180° - 100°
\]
\[
x = 80°
\]

If the angles are part of a linear pair, they would add up to 180° as well. In that case, the missing angle would also be calculated the same way:

\[
x = 180° - (15° + 85°) = 80°
\]

Therefore, in both scenarios, the missing angle is \( 80° \).