Answer:
A. 12 ft², 16 ft², and 20 ft²
Step-by-step explanation:
Answer:
27
Step-by-step explanation:
Tama poyan
27+27=54
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Answer:
Area required for circular hot tube = 6,218 inch² (Approx.)
Step-by-step explanation:
Given:
Diameter of circular hot tube = 89 inches
Value of π = 3.14
Find:
Area required for circular hot tube
Computation:
Radius of hot tube = Diameter / 2
Radius of hot tube = 89 / 2 inches
Area required for circular hot tube = Area of circle
Area of circle = πr²
Area required for circular hot tube = πr²
Area required for circular hot tube = (3.14)(89/2)²
Area required for circular hot tube = (3.14)(7921 / 4)
Area required for circular hot tube = (3.14)(1,980.25)
Area required for circular hot tube = 6,217.985
Area required for circular hot tube = 6,218 inch² (Approx.)
Answer:
The half-life of the radioactive substance is of 3.25 days.
Step-by-step explanation:
The amount of radioactive substance is proportional to the number of counts per minute:
This means that the amount is given by the following differential equation:

In which k is the decay rate.
The solution is:

In which Q(0) is the initial amount:
8000 counts per minute on a Geiger counter at a certain time
This means that 
500 counts per minute 13 days later.
This means that
. We use this to find k.







So

Determine the half-life of the radioactive substance.
This is t for which Q(t) = 0.5Q(0). So







The half-life of the radioactive substance is of 3.25 days.