A sample of a radioactive isotope had an initial mass of 730 mg in 2000 and decays exponentially over time. A measurement in the year 2002
found that the sample's mass had decayed to 510 mg. What would be the
expected mass of the sample in the year 2011, to the nearest whole number?

sup

step-by-step explanation:

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.