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John calculates an arc length involving a circle with a radius of 9 inches. The associated central angle has a measure of [tex]3\pi[/tex] radians. John's work is shown.

John's Work

Step 1:
Central angle (radians) [tex]=\frac{\text{arc length}}{\text{radius}}[/tex]

Step 2:
[tex]3\pi=\frac{\text{arc length}}{9}[/tex]

Step 3:
[tex]\text{arc length}=\frac{\pi}{3}[/tex]

John made his first error in step [tex]\square[/tex]. He [tex]\square[/tex], but he should have [tex]\square[/tex].



Answer :

Sure, let's address John's solution step by step to identify his error and the correct approach.

Step 1:
John correctly sets up the formula for the central angle in radians:
[tex]\[ \text{Central angle (radians)} = \frac{\text{arc length}}{\text{radius}} \][/tex]

Step 2:
He correctly substitutes the given central angle and radius into the formula:
[tex]\[ 3\pi = \frac{\text{arc length}}{9} \][/tex]

Step 3:
Here, John should solve for the arc length. The correct operation to isolate the arc length is to multiply both sides by the radius (9):
[tex]\[ \text{arc length} = 3\pi \times 9 = 27\pi \][/tex]

Thus, the error John made was in step 3. He incorrectly divided instead of multiplying by the radius. Therefore, the correct statements are:

John made his first error in step 3. He divided instead of multiplying, but he should have multiplied by 9.

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