The sum of the degree measures of the three angles of a parallelogram is 300 degrees.

The sum of the degree measures of the three angles of a parallelogram is 300 degrees. Find the magnitude of the obtuse angle of this parallelogram.

1. A, B, C, d – the tops of the parallelogram. ∠А + ∠В + ∠С = 300 °.

2. Considering that the total value of all angles of the parallelogram is 360 °, we calculate the degree measure ∠Д:

∠D = 360 – ∠А – ∠В – ∠С = 60 °.

3. We calculate the degree measure ∠С, using the parallelogram property that the sum of the angles on one side is 180 °:

∠С = 180 ° – 60 ° = 120 °. The indicated angle is obtuse, since its value is greater than 90 °, but less than 180 °.

Answer: The obtuse angle of the parallelogram is 120 °.