Final answer:
To find out if PQRS is a parallelogram, the slopes of opposite sides are calculated. The slopes of PQ and RS are both 1/2, and the slopes of QR and SP are both -2/3. Since opposite sides have equal slopes, PQRS is a parallelogram.
Step-by-step explanation:
To determine if quadrilateral PQRS with vertices P(4, 5), Q(6, 6), R(9, 4), and S(7, 2) is a parallelogram, we have to calculate the slopes of the sides. The slope of a line passing through two points (x₁, y₁) and (x₂, y₂) is (y₂ - y₁)/(x₂ - x₁).
Calculating the slopes:
SP slope = (5 - 2)/(4 - 7) = -2/3
The slopes of PQ and RS are equal, and the slopes of QR and SP are equal, which implies that opposite sides are parallel and that PQRS is a parallelogram according to the slope criteria.