I need the work also i don’t only need the answer i need the work also!!help please

What situation is an example of an observational study

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 33 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30 ∘c on monday, but decreased at a constant rate in the next 33 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.

Plz ( true - false) all triangles have interior angles whose measure sum to 90.