Solve the Problem $$\pi r ^ { 2 },$$ , Where π Is an Irrational Number

question 102

Multiple Choice

Solve the problem.
-The area of a circle of radius r is given by the polynomialal $$\pi r ^ { 2 },$$ , where π is an irrational number. Use 3.14 as an approximation of $\pi ,$ and find the area of a circle with radius 7 cm.

• A) \(147 \mathrm {~cm} ^ { 2 }\)
• B) \(21.98 \mathrm {~cm} ^ { 2 }\)
• C) \(153.86 \mathrm {~cm} ^ { 2 }\)
• D) \(43.96 \mathrm {~cm} ^ { 2 }\)

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Definitions:

Impedance

A measurement of resistance to the flow of alternating current in a circuit, represented by the symbol Z and measured in ohms.

Power Factor

A comparison of the true power (watts) to the apparent power (volt-amperes) in an AC circuit.

Inductive Reactance

The opposition that inductors present to the flow of alternating current, due to the phase shift between voltage and current, measured in ohms.

Coil

An electrical component made by winding conducting wire around a core or forming it into a loop or series of loops, often used in inductors and transformers.