Answer:
31/8
Step-by-step explanation:
Answer:
t = ln(0.5)/-r
Step-by-step explanation:
The decay rate parameter is missing. I will assume a value of 4% per day.
The exponential decay is modeled by the following equation:
A = A0*e^(-r*t)
where A is the mass after t time (in days), A0 is the initial mass and r is the rate (as a decimal).
At half-life A = A0/2, then:
A0/2 = A0*e^(-0.04*t)
0.5 = e^(-0.04*t)
ln(0.5) = -0.04*t
t = ln(0.5)/-0.04
t = 17.33 days
In general the half-life time is:
t = ln(0.5)/-r
??? What is the rest of the question?
Area of the circle can be calculated using the following rule:
area = pi*(radius)^2
For the first circle:
We are given that:
area = 1040.9 square units ....> I
For the second circle:
We are given that:
radius = 27 units
Therefore:
area = pi * (27)^2 = 2290.221044 square units ....> II
For the third circle:
We are given that:
circumference = 87.92 units
Therefore:
circumference = 2*pi*radius = 87.92
radius = 13.99 units
area = pi*(13.99)^2 = 615.12799 square units ...> III
For the fourth circle:
We are given that:
diameter = 19 units
Therefore:
radius = 19/2 = 9.5 units
area = pi*(9.5)^2 = 283.528 square units ....> IV
Based on the above, the order according to increasing area would be:
IV , III , I , II
hope this helps :)
