If the arc of a circle is 15 meters long and the radius of the circle is 3 meters, then what is the measure of the central angle, to the nearest tenth of a degree, that intercepts that 15-meter arc?

(1 point)
• 7.9 degrees
• 282.7 degrees
353.4 degrees
• 286.5 degrees

1 answer

To find the measure of the central angle that intercepts a given arc length in a circle, we can use the formula:

\[ \text{Arc Length} = r \cdot \theta \]

where:

  • \(\text{Arc Length}\) is the length of the arc,
  • \(r\) is the radius of the circle,
  • \(\theta\) is the central angle in radians.

Given that the arc length is 15 meters and the radius is 3 meters, we can rearrange the formula to solve for \(\theta\):

\[ \theta = \frac{\text{Arc Length}}{r} \]

Substituting in the values:

\[ \theta = \frac{15}{3} = 5 \text{ radians} \]

Now, to convert radians to degrees, we use the conversion factor \( \frac{180}{\pi} \):

\[ \theta \text{ (in degrees)} = \theta \text{ (in radians)} \times \frac{180}{\pi} \]

Substituting the value of \(\theta\):

\[ \theta = 5 \times \frac{180}{\pi} \approx 5 \times 57.2958 \approx 286.478 \text{ degrees} \]

Rounding to the nearest tenth:

\[ \theta \approx 286.5 \text{ degrees} \]

Therefore, the measure of the central angle that intercepts the 15-meter arc is 286.5 degrees.