Deductive reasoning is one that necessarily follows, not one that likely follows (this would be an inductive reasoning).
Here the important information is that all squares are also parallellograms, which means that they also necesarily have all the properties of the parallelogram - the correct answer is D.
The answer of the equation is 18.
Do you by any chance have a diagram of the circle or the r value?
40 goes into 120 3 times, so the answer would be 120 - 40.
Which leaves you with 80 people still at the party.
