Question

If the perimeter of a circle is 40 meters, find out the radius of the circle.

• A. 6.23 m
• B. 6.20 m
• C. 6.28 m
• D. 6.36 m

Hint:

Using the approximation $\pi \approx \frac{22}{7}$ simplifies calculations:
$r = \frac{20}{\frac{22}{7}} = \frac{140}{22} \approx 6.36 \text{ m}$.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The perimeter (circumference) of a circle is the total distance around its boundary.
Key Formula or Approach:
The formula for the circumference $C$ of a circle is: \[ C = 2\pi r \] Where $r$ is the radius of the circle.

Step 2: Detailed Explanation:
Given value: \[ C = 40 \text{ m} \] Substitute this into the formula: \[ 2\pi r = 40 \] \[ r = \frac{40}{2\pi} = \frac{20}{\pi} \] Substitute the value of $\pi \approx 3.14159$: \[ r = \frac{20}{3.14159} \approx 6.366 \text{ m} \] Rounding to two decimal places, the radius is approximately $6.36 \text{ m}$ (or $6.37\text{ m}$).

Step 3: Final Answer:
The radius is approximately $6.36 \text{ m}$, which corresponds to Option (D).