jugolo1 wrote:

Each side of a certain parallelogram has length 6. if the area of the parallelogram is 18.

which of the following is the measure of one of its angles?

A. 30’ B. 45’ C. 60’ D. 90’ E.120’

Equal sides of a parallegrame means it's a rhombus -> angle should be either 60 or 120?

Well, you could rule out 60 and 120 right away, because if the parallelogram had an angle of 60 degrees, it would also need to have an angle of 120 degrees (adjacent angles in a parallelogram add to 180), and then there would be two correct answers to the question, which can't happen.

The area of a parallelogram is base*height. The height of this parallelogram must be 3. We therefore need to find the angles in a right angled triangle with a hypotenuse of 6 and a height of 3. That's a 30-60-90, of course, and 30 is the angle opposite the 3, so 30 degrees is one of the angle measures in the parallelogram, and 150 the other.

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