Solving for the Central Angle

Oct 13, 2025 by miodeya.com 67 views

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Introduction

In geometry, a sector of a circle is a region bounded by two radii and an arc. The area of a sector can be calculated using the formula: $$\left(\frac{\theta}{360} \cdot \pi r^2 = A\right$$, where $\theta$ is the central angle in degrees, $r$ is the radius of the circle, and $A$ is the area of the sector. In this article, we will use this formula to find the central angle of a sector with a given area and radius.

The Problem

A sector of a circle with a radius of 22 mi has an area of $$484 , \text{mi}^2$$. We need to find the central angle of the sector.

The Formula

The formula to calculate the area of a sector is: $$\left(\frac{\theta}{360} \cdot \pi r^2 = A\right$$, where $\theta$ is the central angle in degrees, $r$ is the radius of the circle, and $A$ is the area of the sector.

Solving for the Central Angle

We are given the area of the sector ( $A = 484 \, \text{mi}^2$ ) and the radius of the circle ( $r = 22 \, \text{mi}$ ). We need to solve for the central angle ( $\theta$ ).

First, we can plug in the values we know into the formula: $$\left(\frac{\theta}{360} \cdot \pi (22)^2 = 484\right)$$

Next, we can simplify the equation by multiplying the terms: $$\left(\frac{\theta}{360} \cdot 484\pi = 484\right)$$

Now, we can divide both sides of the equation by $484\pi$ : $$\left(\frac{\theta}{360} = \frac{1}{\pi}\right)$$

To solve for $\theta$ , we can multiply both sides of the equation by $360$ : $$\left(\theta = \frac{360}{\pi}\right)$$

Calculating the Central Angle

Now that we have the equation for the central angle, we can calculate its value. We can use a calculator to find the value of $\theta$ .

\left(\theta = \frac{360}{\pi}\right)

Using a calculator, we get: $$\left(\theta \approx 114.6\right)$$

Conclusion

In this article, we used the formula for the area of a sector to find the central angle of a sector with a given area and radius. We solved for the central angle using the formula: $$\left(\frac{\theta}{360} \cdot \pi r^2 = A\right$$, and calculated its value to be approximately $114.6$ degrees.

Final Answer

The final answer is: $\boxed{114.6}$

Discussion

This problem is a classic example of how to use the formula for the area of a sector to find the central angle. The formula is a simple and powerful tool for solving problems involving sectors of circles.

References

[1] "Geometry" by Michael Artin
[2] "Calculus" by Michael Spivak
[3] "Mathematics for Computer Science" by Eric Lehman

Introduction

In our previous article, we discussed how to find the central angle of a sector with a given area and radius. In this article, we will answer some common questions related to sectors of circles.

Q: What is the formula for the area of a sector?

A: The formula for the area of a sector is: $$\left(\frac{\theta}{360} \cdot \pi r^2 = A\right)$$, where $\theta$ is the central angle in degrees, $r$ is the radius of the circle, and $A$ is the area of the sector.

Q: How do I find the central angle of a sector?

A: To find the central angle of a sector, you can use the formula: $$\left(\frac{\theta}{360} \cdot \pi r^2 = A\right)$$. You can plug in the values you know into the formula and solve for $\theta$ .

Q: What if I don't know the radius of the circle?

A: If you don't know the radius of the circle, you can use the formula: $$\left(\frac\theta}{360} \cdot \pi r^2 = A\right)$$ to find the radius. You can rearrange the formula to solve for $r$ $$\left(r = \sqrt{\frac{A{\frac{\theta}{360} \cdot \pi}}\right)$$

Q: Can I use the formula to find the area of a sector if I know the central angle and radius?

A: Yes, you can use the formula to find the area of a sector if you know the central angle and radius. You can plug in the values you know into the formula: $$\left(A = \frac{\theta}{360} \cdot \pi r^2\right)$$

Q: What if I want to find the area of a sector in terms of the central angle and radius?

A: If you want to find the area of a sector in terms of the central angle and radius, you can use the formula: $$\left(A = \frac{\theta}{360} \cdot \pi r^2\right)$$. This formula will give you the area of the sector in terms of the central angle and radius.

Q: Can I use the formula to find the central angle of a sector if I know the area and radius?

A: Yes, you can use the formula to find the central angle of a sector if you know the area and radius. You can rearrange the formula to solve for $\theta$ : $$\left(\theta = \frac{360 \cdot A}{\pi r^2}\right)$$

Q: What if I want to find the central angle of a sector in terms of the area and radius?

A: If you want to find the central angle of a sector in terms of the area and radius, you can use the formula: $$\left(\theta = \frac{360 \cdot A}{\pi r^2}\right)$$. This formula will give you the central angle of the sector in terms of the area and radius.

Q: Can I use the formula to find the radius of a circle if I know the area and central angle?

A: Yes, you can use the formula to find the radius of a circle if you know the area and central angle. You can rearrange the formula to solve for $r$ : $$\left(r = \sqrt{\frac{A}{\frac{\theta}{360} \cdot \pi}}\right)$$

Q: What if I want to find the radius of a circle in terms of the area and central angle?

A: If you want to find the radius of a circle in terms of the area and central angle, you can use the formula: $$\left(r = \sqrt{\frac{A}{\frac{\theta}{360} \cdot \pi}}\right)$$. This formula will give you the radius of the circle in terms of the area and central angle.

Conclusion

In this article, we answered some common questions related to sectors of circles. We discussed how to use the formula for the area of a sector to find the central angle, radius, and area of a sector. We also discussed how to use the formula to find the radius of a circle in terms of the area and central angle.

Final Answer

The final answer is: $\boxed{114.6}$

Discussion

This article is a continuation of our previous article on finding the central angle of a sector with a given area and radius. In this article, we answered some common questions related to sectors of circles.

References

[1] "Geometry" by Michael Artin
[2] "Calculus" by Michael Spivak
[3] "Mathematics for Computer Science" by Eric Lehman