Solve the Problem $\mathrm { A } = \pi \mathrm { r } ^ { 2 }$

question 538

Multiple Choice

Solve the problem.
- $\mathrm { A } = \pi \mathrm { r } ^ { 2 }$ , where $\mathrm { r }$ is the radius, in centimeters. By approximately how much does the area of a circle decrease when the radius is decreased from $4.0 \mathrm {~cm}$ to $3.9 \mathrm {~cm}$ ? (Use $3.14$ for $\pi$ .)

• A) \(1.3 \mathrm {~cm} ^ { 2 }\)
• B) \(2.3 \mathrm {~cm} ^ { 2 }\)
• C) \(2.5 \mathrm {~cm} ^ { 2 }\)
• D) \(2.7 \mathrm {~cm} ^ { 2 }\)

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Definitions:

Perfect Substitute

Goods that can be used in place of one another with no loss of utility for the consumer, indicating a one-to-one substitutability.

Utility Function

A mathematical representation that assigns a level of utility or satisfaction to different bundles of goods, allowing preferences to be compared quantitatively.

Indifference Curve

A graph showing different bundles of goods between which a consumer is indifferent, meaning that the consumer has no preference for one bundle over the other.

Apples

Commonly refers to the fruit of the apple tree, but in economic terms, it can represent a simple, tangible commodity for analysis.