Find the missing angles using either the triangle sum theorem (a2+b2=c2) or inverse trigonometric ratios

Which approach to the theory-and-research cycle does the following sequence reflect: (1) specific observations suggest generalizations, (2) generalizations produce a tentative theory, (3) the theory is tested through the formation of hypotheses, and (4) hypotheses may provide suggestions for additional observations?

How do you find the circumfrance of a circle?

The owner of the plant nursery where you were tells you to fill 350 ml bottles from a 30 l from a fertilizer