Final answer:
To calculate the interior angle, subtract the given angles from 180 degrees.
Step-by-step explanation:
An interior angle is the angle formed by two sides of a polygon inside its boundary. To calculate the interior angle, we need to subtract the given angles from 180 degrees.
15° 22' 45'' can be written as 15 + (22/60) + (45/3600) degrees, and 20° 15' 40'' can be written as 20 + (15/60) + (40/3600) degrees.
Then, the interior angle is 180 - (15 + (22/60) + (45/3600)) - (20 + (15/60) + (40/3600)) degrees.