To find the circumference and area of a circle with a radius of 4.5 cm, we can use the following formulas:
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Circumference (C) of a circle is given by the formula: \[ C = 2 \pi r \] where \( r \) is the radius.
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Area (A) of a circle is given by the formula: \[ A = \pi r^2 \]
Using \( \pi \approx 3.14 \) and \( r = 4.5 \) cm:
Circumference Calculation
\[ C = 2 \times 3.14 \times 4.5 \] \[ C \approx 2 \times 3.14 \times 4.5 = 28.26 \text{ cm} \]
Rounding to the nearest tenth: \[ C \approx 28.3 \text{ cm} \]
Area Calculation
\[ A = 3.14 \times (4.5)^2 \] Calculating \( (4.5)^2 \): \[ (4.5)^2 = 20.25 \] Now substituting back: \[ A \approx 3.14 \times 20.25 = 63.57 \text{ cm}^2 \]
Rounding to the nearest tenth: \[ A \approx 63.6 \text{ cm}^2 \]
Final Answers
- Circumference: \( 28.3 \text{ cm} \)
- Area: \( 63.6 \text{ cm}^2 \)