The perimeter of parallelogram ABCD is 80 cm, A = 30 °, and the perpendicular BH to line AD is 7.5 cm.

The perimeter of parallelogram ABCD is 80 cm, A = 30 °, and the perpendicular BH to line AD is 7.5 cm. Find the sides of the parallelogram.

Since, according to the condition, ВН is perpendicular to AD, then the ABН triangle is rectangular, in which the ВAН angle, by condition, is 30.

Then the ВН leg lies opposite the angle 30, which means it is equal to half the length of the hypotenuse.

BH = AB / 2. Then AB = 2 * BH = 2 * 7.5 = 15 cm.

In a parallelogram, the lengths of the opposite sides are equal. AB = CD = 15 cm. BC = AD.

The perimeter of the parallelogram is: Ravsd = 2 * (AB + BC) = 80.

AB + BC = 40.

BC = 40 – AB = 40 – 15 = 25 cm.

Answer: The sides of the parallelogram are 15 cm and 25 cm.



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