Calculate the circumference.
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Calculate the circumference.
To solve the problem of finding the circumference of a circle with radius , we will follow these steps:
Let's go through these steps in detail:
Step 1: The radius is given as .
Step 2: The formula for the circumference of a circle is .
Step 3: Substitute the given radius into the formula:
Using the value of , we can calculate:
Therefore, the circumference of the circle is approximately .
43.982
\( r=11 \)
Calculate the circumference.
Radius goes from the center to the edge (like the line in your diagram). Diameter goes all the way across through the center. Diameter = 2 × radius, so with r = 7, diameter = 14.
For most problems, π ≈ 3.14159 gives enough accuracy. Some teachers want the exact answer as 14π, others want the decimal 43.982. Check what your teacher prefers!
Think of circumference as 2 semicircles. Each semicircle has length πr, so the full circle is 2 × πr = 2πr. It's like wrapping string around the circle!
Remember: C = 2πr or C = πd. Think "2 pi r" or "pi times diameter". Both give the same answer - use whichever measurement you're given.
The circumference should be about 6 times the radius (since 2π ≈ 6.28). With r = 7: 6 × 7 = 42, which is close to 43.982. This confirms our answer makes sense!
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