The Spread of a Contaminant Is Increasing in a Circular $r ( t ) = 2.25 \sqrt { t }$

question 226

Multiple Choice

The spread of a contaminant is increasing in a circular pattern on the surface of a lake.The radius of the contaminant can be modeled by $r ( t ) = 2.25 \sqrt { t }$ , where r is the radius in meters and t is the time in hours since contamination.
Find a function that gives the area A of the circular lake in terms of the time since the spread began.

• A) \(A \circ r ( t ) = 5.0625 \pi \sqrt { t }\)
• B) \(A \circ r ( t ) = 2.25 \pi t\)
• C) \(A \circ r ( t ) = 5.0625 t\)
• D) \(A \circ r ( t ) = 5.0625 \sqrt { t }\)
• E) \(A \circ r ( t ) = 5.0625 \pi t\)

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Definitions:

Sexual Frequency

A term that refers to the number of times sexual activity occurs within a specific time period.

Independent Variable

In an experiment, a factor that can be manipulated or changed.

Dependent Variable

In an experiment, a factor that is likely to be affected by changes in the independent variable.