Recall that the two acute angles of a right triangle add up to 90 degrees.
Let s be the measure (in degrees) of the smallest angle of the given right triangle, then we can set the following equation:
Adding like terms we get:
Subtracting 40 from the above result we get:
Dividing the above result by 2 we get:
Therefore the measure of the smallest angle is 25º.
Answer: 25º.