An arc of a circle has a length of 2.5π units. If the circle it comes from has a
radius of 4 units, what is the measure of the central angle associated with this arc?



Answer :

Sure, let's break this problem down step-by-step:

1. Identify the given values:
- Arc length, [tex]\(s\)[/tex], is [tex]\(2.5\pi\)[/tex] units.
- Radius, [tex]\(r\)[/tex], is 4 units.

2. Use the formula to find the central angle in radians:
The formula to find the central angle (θ) in radians is:
[tex]\[ \theta = \frac{s}{r} \][/tex]

3. Substitute the given values into the formula:
[tex]\[ \theta = \frac{2.5\pi}{4} \][/tex]

4. Simplify the fraction:
[tex]\[ \theta = \frac{2.5\pi}{4} = \frac{5\pi}{8} \text{ radians} \][/tex]

So, the measure of the central angle in radians is [tex]\(\frac{5\pi}{8}\)[/tex] radians.

5. Convert the central angle from radians to degrees:
To convert radians to degrees, we use the conversion factor [tex]\(\frac{180}{\pi}\)[/tex]:
[tex]\[ \theta \text{ (in degrees)} = \theta \text{ (in radians)} \times \frac{180}{\pi} \][/tex]

6. Apply the conversion factor:
[tex]\[ \theta \text{ (in degrees)} = \frac{5\pi}{8} \times \frac{180}{\pi} \][/tex]

7. Simplify and perform the calculations:
[tex]\[ \theta \text{ (in degrees)} = \frac{5 \times 180}{8} \][/tex]
[tex]\[ \theta \text{ (in degrees)} = \frac{900}{8} = 112.5 \text{ degrees} \][/tex]

Thus, the measure of the central angle associated with the arc is [tex]\( \frac{5\pi}{8} \)[/tex] radians or 112.5 degrees.