The diameter of a circle is 5ft. Find the circumference to the nearest tenth

What are potential hypotheses (explanations) regarding why there are ecological equivalents between many metatherians and eutherians? discuss your hypothesis in terms of the processes that could lead to the current ecologies and distributions of metatherians and eutherians.

20 da is equal to a. 2,000 cm. b. 2 m. c. 20,000 cm. d. 20,000 mm

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.