Skip to main content
Ch. 1 - Angles and the Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Non è quello che usi tu?Cambia libro di testo
Capitolo 1, Problema 77

Find the area of the sector of a circle of radius r formed by a central angle θ. Express area in terms of π. Then round your answer to two decimal places. Radius, r: 4 inches Central Angle, θ: θ = 240°

Guida verificata passo dopo passo
1
Recall the formula for the area of a sector of a circle: \(\text{Area} = \frac{\theta}{360^\circ} \times \pi r^2\), where \(\theta\) is the central angle in degrees and \(r\) is the radius.
Substitute the given values into the formula: \(r = 4\) inches and \(\theta = 240^\circ\), so the area becomes \(\frac{240}{360} \times \pi \times 4^2\).
Simplify the fraction \(\frac{240}{360}\) to its lowest terms to make calculations easier.
Calculate \$4^2$ to find the square of the radius.
Multiply the simplified fraction by \(\pi\) and the squared radius to express the area in terms of \(\pi\). Then, use the approximate value of \(\pi \approx 3.1416\) to round the area to two decimal places.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
4m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Area of a Sector

The area of a sector of a circle is the portion of the circle's area enclosed by two radii and the arc between them. It is calculated using the formula (θ/360) × π × r², where θ is the central angle in degrees and r is the radius. This formula scales the full circle's area by the fraction of the circle represented by the angle.
Video consigliato:
Percorso guidato
4:02
Calculating Area of SAS Triangles

Central Angle in Degrees

The central angle θ is the angle formed at the center of the circle by two radii. It determines the size of the sector and is measured in degrees. Understanding how to use this angle in formulas is essential for calculating sector properties like area and arc length.
Video consigliato:
Percorso guidato
04:46
Coterminal Angles

Rounding and Expressing Answers

After calculating the exact area in terms of π, it is often necessary to provide a numerical approximation. This involves substituting π ≈ 3.1416 and rounding the result to a specified number of decimal places, here two, to present a clear and practical answer.
Video consigliato:
Percorso guidato
6:36
Simplifying Trig Expressions