In a right triangle, the sum of the angles is always 180 degrees. One of the angles is a right angle (90 degrees).
Given that one of the other angles is 3.5 degrees, we can find the measure of the third angle by using the following formula:
\[ \text{Third Angle} = 180^\circ - 90^\circ - 3.5^\circ \]
Calculating this gives:
\[ \text{Third Angle} = 180^\circ - 90^\circ - 3.5^\circ = 86.5^\circ \]
Thus, the measure of the third angle in the triangle is 86.5 degrees.