In Exercises 55–58, use a calculator to find the value of the acute angle θ to the nearest degree. tan θ = 4.6252
Ch. 1 - Angles and the Trigonometric Functions

Chapter 1, Problem 1.1.75
In Exercises 75–78, 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: 10 meters Central Angle, θ: θ = 18°
Verified step by step guidance1
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 of the circle.
Substitute the given values into the formula: \(r = 10\) meters and \(\theta = 18^\circ\), so the area becomes \(\frac{18}{360} \times \pi \times 10^2\).
Simplify the fraction \(\frac{18}{360}\) to its lowest terms to make calculations easier.
Calculate the expression \(\pi \times 10^2\) which represents the area of the full circle, then multiply by the simplified fraction to find the sector area in terms of \(\pi\).
Finally, use the approximate value of \(\pi \approx 3.1416\) to compute the numerical value of the sector area and round your answer to two decimal places.

Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
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 as (θ/360) × π × r² when θ is in degrees, where r is the radius and θ is the central angle.
Recommended video:
Guided course
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. When given in degrees, it must be used directly in the sector area formula as a fraction of 360°, representing the full circle.
Recommended video:
Coterminal Angles
Rounding Numerical Results
After calculating the exact area in terms of π, numerical approximation involves substituting π ≈ 3.1416 and rounding the final answer to the specified decimal places, here two decimals, to provide a practical and understandable result.
Recommended video:
Find the Angle Between Vectors
Related Practice
Textbook Question
630
views
Textbook Question
In Exercises 41–56, use the circle shown in the rectangular coordinate system to draw each angle in standard position. State the quadrant in which the angle lies. When an angle's measure is given in radians, work the exercise without converting to degrees.
420°
625
views
Textbook Question
Find the reference angle for each angle.
4.7
711
views
Textbook Question
In Exercises 1–8, use the Pythagorean Theorem to find the length of the missing side of each right triangle. Then find the value of each of the six trigonometric functions of θ.
719
views
Textbook Question
In Exercises 1–6, the measure of an angle is given. Classify the angle as acute, right, obtuse, or straight. 135°
807
views
Textbook Question
In Exercises 61–86, use reference angles to find the exact value of each expression. Do not use a calculator. tan(9𝜋/2)
732
views
