Suppose that Prolog facts are used to define the predicates mother(M, Y) and father(F, X), which represent that M is the mother of Y and F is the father of X, respectively. Give a Prolog rule to define the predicate grandfather(X, Y), which represents that X is the grandfather of Y. Use a comma to denote "and" and a semicolon to denote "or."

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.