Question

A student solved for the radius of a circle with a circumference of 12π Step 1: C = 2 pi r. Step 2: 12 pi = 2 pi r. Step 3: StartFraction 12 pi over 2 pi EndFraction = StartFraction 2 pi r over 2 pi EndFraction. Step 4: 6 = pi r. Step 5: StartFraction 6 over pi EndFraction = StartFraction pi r over pi EndFraction. Step 6: Solving for r, the length of the radius is StartFraction 6 over pi EndFraction centimeters. In which step did the student make an error? Step . Solving for r, the length of the radius should be cm.

Answer 1

4

6

Explanation:

just had the question peeps (。・ω・。)

Answer 2

The student made a mistake in step 4

The length of the radius should be 6 cm

Explanation:

Let us write each step to find the radius of a circle from its circumference

Step 1:

∵ C = 2πr

∵ C = 12π

Step 2:

Equate 12π by 2πr

∴ 12π = 2πr

Step 3:

Divide both sides by 2π

∵
`(12\pi )/(2\pi )=(2\pi r)/(2\pi )`

Step 4:

∴ 6 = r

∴ The radius of the circle is 6 cm

The student mad a mistake he divided the left hand side by 2π and the right hand side by 2 only he left π with r

Step 4:

∴ 6 = πr

So he divided both sides again by π

Step 5:

∵
`(6)/(\pi )=(\pi r)/(\pi )`

Step 7:

∴
`(6)/(\pi )` = r

The student made a mistake in step 4

The length of the radius should be 6 cm