Math Problem Statement

One a circle of radius 24 in, find the length of arc subtended by a central angle of (a) 2/3 rad, (b) 3 phi/5 rad,(c) 75°, (d) 130°

Solution

To find the length of an arc subtended by a central angle in a circle, we use the formula:

Arc Length=r×θ\text{Arc Length} = r \times \theta

where:

  • rr is the radius of the circle.
  • θ\theta is the central angle in radians.

Given:

  • Radius r=24r = 24 inches.

Let's find the arc lengths for each of the given angles:

(a) θ=23\theta = \frac{2}{3} radians

Arc Length=24×23=24×0.6667=16 inches\text{Arc Length} = 24 \times \frac{2}{3} = 24 \times 0.6667 = 16 \text{ inches}

(b) θ=3π5\theta = \frac{3\pi}{5} radians

Arc Length=24×3π5=24×1.884=45.21 inches\text{Arc Length} = 24 \times \frac{3\pi}{5} = 24 \times 1.884 = 45.21 \text{ inches}

(c) θ=75\theta = 75^\circ

First, convert degrees to radians:

θ=75×π180=75π180=5π12 radians\theta = 75^\circ \times \frac{\pi}{180^\circ} = \frac{75\pi}{180} = \frac{5\pi}{12} \text{ radians}

Then, calculate the arc length:

Arc Length=24×5π12=24×1.309=31.42 inches\text{Arc Length} = 24 \times \frac{5\pi}{12} = 24 \times 1.309 = 31.42 \text{ inches}

(d) θ=130\theta = 130^\circ

Convert degrees to radians:

θ=130×π180=130π180=13π18 radians\theta = 130^\circ \times \frac{\pi}{180^\circ} = \frac{130\pi}{180} = \frac{13\pi}{18} \text{ radians}

Then, calculate the arc length:

Arc Length=24×13π18=24×2.268=54.43 inches\text{Arc Length} = 24 \times \frac{13\pi}{18} = 24 \times 2.268 = 54.43 \text{ inches}

Summary of Results:

  • (a) 23\frac{2}{3} radians: 16 inches
  • (b) 3π5\frac{3\pi}{5} radians: 45.21 inches
  • (c) 7575^\circ: 31.42 inches
  • (d) 130130^\circ: 54.43 inches

Would you like more details on any of these steps or have any other questions?


Related Questions:

  1. How do you convert radians to degrees and vice versa?
  2. What is the formula for the circumference of a circle?
  3. How do you calculate the area of a sector of a circle?
  4. What is the difference between a major arc and a minor arc?
  5. How do you find the length of an arc when the central angle is given in degrees?

Tip: Remember, when converting between degrees and radians, 180=π180^\circ = \pi radians.

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Math Problem Analysis

Mathematical Concepts

Geometry
Circle
Arc Length
Radians
Degrees

Formulas

Arc Length Formula: arc length = radius * central angle

Theorems

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Suitable Grade Level

Grades 9-12