Question

circumference
match each radius or diameter with the circumference of the circle. approximate.
diameter = 4 cm
radius = 4 cm
radius = 8 cm
c ≈ 16 cm
c ≈ 4π cm
c ≈ 8π cm

Explanation:

Step1: Recall Circumference Formula

The formula for the circumference \( C \) of a circle is \( C = \pi d \) (where \( d \) is the diameter) or \( C = 2\pi r \) (where \( r \) is the radius), and we'll use \( \pi \approx 3.14 \) for approximation.

Step2: Calculate for Diameter = 4 cm

Using \( C=\pi d \), substitute \( d = 4 \) cm and \( \pi\approx3.14 \):
\( C = 3.14\times4 = 12.56 \) cm.

Step3: Calculate for Radius = 4 cm

Using \( C = 2\pi r \), substitute \( r = 4 \) cm and \( \pi\approx3.14 \):
\( C = 2\times3.14\times4 = 25.12 \) cm.

Step4: Calculate for Radius = 8 cm

Using \( C = 2\pi r \), substitute \( r = 8 \) cm and \( \pi\approx3.14 \):
\( C = 2\times3.14\times8 = 50.24 \) cm.

Step5: Match the Calculations

• Diameter = 4 cm: \( C = 12.56 \) cm (matches the first circumference option, likely "C ≈ 12.56 cm").
• Radius = 4 cm: \( C = 25.12 \) cm (matches the second circumference option, likely "C ≈ 25.12 cm").
• Radius = 8 cm: \( C = 50.24 \) cm (matches the third circumference option, likely "C ≈ 50.24 cm").

Answer:

• Diameter = 4 cm → \( C \approx 12.56 \) cm
• Radius = 4 cm → \( C \approx 25.12 \) cm
• Radius = 8 cm → \( C \approx 50.24 \) cm