Answer:
Area of a parallelogram is base times height. Note that CD = AB & AD = BC
to find the height, draw a line from angle B perpendicular to the base b. Lets call the point of intersection at the base E. This constitutes a right triangle with AB as the hypotenuse. Using the law of sine to calculate the height h:
h/sin(A) = AB/sin(90°) ( sin(90°) = 1)
h = AB * sin(45°)
h = 10 * sin(45°)
Area = 14 * 10 * sin(45°) = 140 * sin(45°) ≈ 98.99 QEDexplanation: