Each side of a certain parallelogram has length 5

Each side of a certain parallelogram has length 5. If the area of the parallelogram is 20. Which of the following is the measure of one of its angles?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #41665