Final answer:
The angle formed by ray BA and ray BC is 58 degrees, found by adding the measures of the angles formed by rays BA and BD, and BD and BC.
Step-by-step explanation:
The student is asking about the measurement of angles formed by three rays starting from a common point. To find the measure of the angle formed by ray BA and ray BC, you need to add the measure of the angle formed by ray BA and ray BD (which is 37 degrees) to the measure of the angle formed by ray BD and ray BC (which is 21 degrees). Therefore, the total measure of the angle formed by ray BA and ray BC is 58 degrees.