Final answer:
The hypothesis of the conditional statement "A right angle has a measure of 90°" is "A right angle".
Step-by-step explanation:
When you write the statement "A right angle has a measure of 90°" as a conditional statement, the hypothesis is the 'if' part of the statement. In this case, the hypothesis would be "A right angle". The rest of the statement following the hypothesis is the conclusion. Therefore, the conditional statement would be "If it is a right angle, then it has a measure of 90°".