The calculated measure of the angle KM is 159 degrees
How to determine the measure of the angle KM
From the question, we have the following parameters that can be used in our computation:
The circle
The sum of angles in a semi-circle is 180 degrees
Using the above as a guide, we have the following:
KM = 180 - 21
Evaluate
KM = 159
Hence, the measure of the angle KM is 159 degrees