Question

On a coordinate plane, parallelogram A B C D has points (3, 6), (6, 5), (5, 1), and (2, 2).
What is the area of parallelogram ABCD?

13 square units
14 square units
15 square units
16 square units

Answer 1

Area = |det(AB, AD)|. With A(3,6), B(6,5), D(2,2):

AB = (3, -1), AD = (-1, -4). det = 3*(-4) - (-1)*(-1) = -12 - 1 = -13, so area = | -13 | = 13.

Answer: 13 square units.