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The numerical value of the area of a cir...

The numerical value of the area of a circla is greater than the numerical value of its circumference. Is this statement true ? Why ?

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To determine whether the statement "The numerical value of the area of a circle is greater than the numerical value of its circumference" is true, we will analyze the formulas for the area and circumference of a circle. ### Step 1: Write down the formulas The area \( A \) of a circle is given by: \[ A = \pi r^2 \] The circumference \( C \) of a circle is given by: \[ C = 2 \pi r \] ### Step 2: Set up the inequality We need to check if the area is greater than the circumference: \[ \pi r^2 > 2 \pi r \] ### Step 3: Simplify the inequality We can divide both sides of the inequality by \( \pi \) (assuming \( \pi > 0 \)): \[ r^2 > 2r \] ### Step 4: Rearrange the inequality Rearranging gives us: \[ r^2 - 2r > 0 \] ### Step 5: Factor the inequality Factoring the left side, we get: \[ r(r - 2) > 0 \] ### Step 6: Determine the intervals To find the values of \( r \) that satisfy this inequality, we can find the roots of the equation \( r(r - 2) = 0 \): - The roots are \( r = 0 \) and \( r = 2 \). Now we can test the intervals: 1. \( r < 0 \) 2. \( 0 < r < 2 \) 3. \( r > 2 \) ### Step 7: Test the intervals - For \( r < 0 \): Choose \( r = -1 \) → \( (-1)(-1 - 2) = (-1)(-3) = 3 > 0 \) (True) - For \( 0 < r < 2 \): Choose \( r = 1 \) → \( (1)(1 - 2) = (1)(-1) = -1 < 0 \) (False) - For \( r > 2 \): Choose \( r = 3 \) → \( (3)(3 - 2) = (3)(1) = 3 > 0 \) (True) ### Step 8: Conclusion The inequality \( r(r - 2) > 0 \) holds true for: - \( r < 0 \) - \( r > 2 \) Thus, the area of the circle is greater than the circumference when the radius \( r \) is either less than 0 (not physically meaningful) or greater than 2. Therefore, the statement "The numerical value of the area of a circle is greater than the numerical value of its circumference" is **not true** for \( 0 < r < 2 \). ### Summary The statement is incorrect because for \( 0 < r < 2 \), the circumference is greater than the area. ---

To determine whether the statement "The numerical value of the area of a circle is greater than the numerical value of its circumference" is true, we will analyze the formulas for the area and circumference of a circle. ### Step 1: Write down the formulas The area \( A \) of a circle is given by: \[ A = \pi r^2 \] The circumference \( C \) of a circle is given by: ...
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