Hypothesis
Biconditional: If a figure is a nonagon, then it has 9 sides.
What is "A figure is a nonagon if and only if it has 9 sides"?
Biconditional of "if the angle's measure is 180 degrees, then it is a straight angle"
What is "an angle's measure is 180 degrees if and only if the angle is a straight angle."
If 7x + 3 = 10, then 7x = 7.
What is the subtraction property of =?
Biconditional of "if you have a pulse, then you are alive."
What is "you have a pulse if and only if you are alive"?