Diagonal BD of parallelogram ABCD makes angles of 45 and 75 degrees with its sides. Find the acute angle of parallelogram.

Determine the value of the angle ABC.

Angle ABC = AВD + СВD = 75 + 45 = 120.

A parallelogram has a sum of adjacent angles equal to 180.

Then the angle ВAD = (180 – ABC) = (180 – 120) = 60.

In a parallelogram, the opposite angles are equal, then the angle of ВСD = ВAD = 600, angle ADС = ABC = 120.

Answer: The acute angle of the parallelogram is 60.



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