Find the length of d

What is the missing reason in step 5? linear pair postulategivendefinition of complementary anglescongruent complements theorem

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 3 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 3 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.

If the scale factor between two circles is 2x/5y what is the ratio of their areas?