Math Problem Statement

On a circle of radius 15 cm, find the length of the arc subtended by a central angle of 85 degrees. Round your answer to the nearest tenth.

Solution

To solve this problem, we will use the formula for the length of an arc LL subtended by a central angle θ\theta in a circle of radius rr:

L=θ360×2πrL = \frac{\theta}{360} \times 2\pi r

Given:

  • r=15cmr = 15 \, \text{cm} (radius of the circle),
  • θ=85\theta = 85^\circ (central angle),
  • π3.1416\pi \approx 3.1416.

Now, let's substitute these values into the formula:

L=85360×2×3.1416×15L = \frac{85}{360} \times 2 \times 3.1416 \times 15

First, calculate the fraction of the circle's circumference:

L=85360×94.248L = \frac{85}{360} \times 94.248

L0.2361×94.248=22.24cmL \approx 0.2361 \times 94.248 = 22.24 \, \text{cm}

Thus, the length of the arc is approximately 22.2 cm (rounded to the nearest tenth).

Would you like further explanation or details?

Here are 5 related questions:

  1. How is the formula for the arc length derived?
  2. What would the arc length be if the central angle were 180 degrees?
  3. How does changing the radius affect the arc length?
  4. Can this formula be applied to radians instead of degrees?
  5. What is the relationship between the arc length and the sector area?

Tip: To convert between degrees and radians, remember that 180=πradians180^\circ = \pi \, \text{radians}.

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Math Problem Analysis

Mathematical Concepts

Geometry
Circle
Arc Length
Central Angle

Formulas

L = (θ/360) × 2πr

Theorems

Arc length formula for circles

Suitable Grade Level

Grades 9-11