Find the measure of arc CDE.

2 over 5 and 4 over 15

don’t know last one sorry

step-by-step explanation:

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

0.5?

hope your goes well, here's a turkey

-thekoolkid1o1