Answer:
The argument is valid by the law of detachment.
Step-by-step explanation:
We first verify that the first statement, "if p, then q" is correct. If a parallelogram has a right angle, this means that the angle opposite that angle must also be right; this is because the opposite angles of a parallelogram are congruent.
This also means that the adjacent angle to this right angle must also be right; this is because the adjacent angles in a parallelogram are supplementary.
Thus "if p, then q" is true.
The law of detachment states that if I have two statements, one of the form "if p, then q" and the other "p", then the conclusion, "q," is valid.
