A triangle has angles 40 and 60 what is the third angle

Steps:

1. The sum of angles in a triangle is always 180 degrees.
2. Add the two given angles: $40^\circ + 60^\circ = 100^\circ$.
3. Subtract this sum from 180 degrees to find the third angle: $180^\circ - 100^\circ = 80^\circ$.