Answer:
D or 176.71 inches squared.
Step-by-step explanation:
the radius is 7.5. put it in a calculator and you get D.
Answer:
3
Step-by-step explanation:
If you notice the y is the change in distance, so #3 has the best explanation.
For this case we have an equation of the form:
y = A * (b) ^ t
Where,
A: initial amount
b: decrease rate
t: time in years.
Substituting values we have:
7 = A * (0.5) ^ ((1/20) * t)
For t = 45 years we have:
7 = A * (0.5) ^ ((1/20) * 45)
Clearing A:
A = 7 / ((0.5) ^ ((1/20) * 45))
A = 33.3
Answer:
the density of the substance when it was deposited 45 years ago was:
A = 33.3 milligrams per square centimeter
