In parallelogram ABCD AB = BD, AD = 12, sinA = 0.8. Find the area of the parallelogram.

Since AB = BD, triangle ABD is isosceles. We will construct the height BH, which is also the median of the triangle ABD, then AH = DH = AD / 2 = 12/2 = 6 cm.

Cos2A = 1 – Sin2A = 1 – 0.64 = 0.36.

CosA = 0.6 = AH / AB.

AB = AH / 0.6 = 6 / 0.6 = 10 cm, then the parallelogram area is:

Savsd = AB * AD * SinA = 10 * 12 * 0.8 = 96 cm2.

Answer: The area of the parallelogram is 96 cm2.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.