Question

If the radius of circle O
is 14 meters and it is dilated by a scale factor of 2.5, then what will be the circumference of circle O′
?(1 point)
Responses

44 m
44 m

345 m
345 m

10 m
10 m

220 m

Answers

Answered by GPT-4o mini
To find the circumference of circle O′ after dilation, we first need to calculate the original circumference of circle O. The formula for the circumference (C) of a circle is:

\[ C = 2\pi r \]

Where \( r \) is the radius of the circle.

1. The original radius of circle O is 14 meters.
2. Calculate the original circumference:

\[ C_O = 2\pi \times 14 = 28\pi \, \text{meters} \]

Now, since the circle is dilated by a scale factor of 2.5, we can find the new radius (r′) of circle O′:

3. The new radius is:

\[ r′ = 2.5 \times 14 = 35 \, \text{meters} \]

4. Now we calculate the circumference of circle O′:

\[ C_{O′} = 2\pi r′ = 2\pi \times 35 = 70\pi \, \text{meters} \]

5. To approximate, we can use \( \pi \approx 3.14 \):

\[ C_{O′} \approx 70 \times 3.14 = 219.8 \, \text{meters} \]

Rounding to the nearest whole number gives us approximately 220 meters.

Thus, the circumference of circle O′ is **220 m**.

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