Answer: Union of two sets.
Explanation: "An element is in the union of two sets if it is in the first set, the second set, or both. The symbol we use for the union is ∪ . The word that you will often see that indicates a union is "or".
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It's difficult to make out, but I think the task is to expand

Write the number in polar form first:

By DeMoivre's theorem, you have

and converting back to Cartesian form, this number is equivalent to
Every square is a rectangle because it is a quadrilateral with all four right angle (a rectangle is not a square)
Answer:
Area of a triangle is base times height divided by 2. The formula for finding the area of a parallelogram is easiest to just break it down into two triangles and 1 square/rectangle. Then just find the area of all then add them together to get the final area.