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Ch. 3 - Radian Measure and The Unit Circle
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161, 9780135440780, 9780136881117, 9780135440827, 9780135924891당신이 사용하는 게 아니라요?교과서 변경
4장, 문제 49

Find the area of a sector of a circle having radius r and central angle θ. Express answers to the nearest tenth. See Example 5. r = 29.2 m, θ = 5π/6 radians

검증된 단계별 안내
1
Recall the formula for the area of a sector of a circle: \(\text{Area} = \frac{1}{2} r^{2} \theta\), where \(r\) is the radius and \(\theta\) is the central angle in radians.
Identify the given values: radius \(r = 29.2\) meters and central angle \(\theta = \frac{5\pi}{6}\) radians.
Substitute the given values into the formula: \(\text{Area} = \frac{1}{2} \times (29.2)^{2} \times \frac{5\pi}{6}\).
Simplify the expression step-by-step: first calculate \(r^{2} = (29.2)^{2}\), then multiply by \(\frac{5\pi}{6}\), and finally multiply by \(\frac{1}{2}\).
After simplifying, round the final result to the nearest tenth to express the area of the sector.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Area of a Sector

The area of a sector of a circle is a portion of the circle's total area, determined by the central angle. It is calculated using the formula A = (1/2) * r² * θ, where r is the radius and θ is the central angle in radians. This formula directly relates the angle to the fraction of the circle's area.
추천 영상:
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Calculating Area of SAS Triangles

Radian Measure

Radians measure angles based on the radius of a circle, where one radian equals the angle subtended by an arc equal in length to the radius. Using radians simplifies formulas in trigonometry and geometry, such as the sector area formula, which requires the angle to be in radians for direct application.
추천 영상:
가이드 코스
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Converting between Degrees & Radians

Rounding and Approximation

After calculating the area, results often need to be rounded to a specified precision, such as the nearest tenth. This involves using decimal approximation of π and performing arithmetic carefully to ensure the final answer meets the required accuracy.
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How to Use a Calculator for Trig Functions