It finally snowing in Texas...

Could answer every question with steps

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angle measure.

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?