Which of the following uses the correct formula to find the approximate circumference of a circle that has a radius of 12? Use 3.14 for π

and express your answer to the hundredths place.(1 point)
Responses

452.16
452.16

18.84
18.84

75.36
75.36

37.68
37.68

Which of the following uses the correct formula to find the approximate circumference of a circle that has a radius of 450?(1 point)
Responses

C≈2⋅3.14⋅450
upper C approximately equals 2 times 3.14 times 450

C≈3.14⋅450÷2
upper C approximately equals 3.14 times 450 divided by 2

C≈3.14⋅4502
upper C approximately equals 3.14 times 450 squared

C≈3.14⋅150

Which formula correctly describes the proportional relationship between the circumference of a circle and the diameter?(1 point)
Responses

π=dC
pi equals Start Fraction d over upper C

Cd=π
Start Fraction upper C over d End Fraction equals pi

C=πd
upper C equals Start Fraction pi over d End Fraction

A=πr2

1 answer

To solve each of your questions, let’s break them down step by step, one at a time.

  1. Finding the approximate circumference of a circle with a radius of 12: The formula to calculate the circumference \(C\) of a circle is: \[ C = 2\pi r \] Given that \(r = 12\) and using \( \pi \approx 3.14 \): \[ C \approx 2 \cdot 3.14 \cdot 12 \] Calculating that: \[ C \approx 2 \cdot 3.14 \cdot 12 = 6.28 \cdot 12 = 75.36 \] So the correct response is: 75.36

  2. Finding the approximate circumference of a circle with a radius of 450: Again using the same circumference formula \(C = 2\pi r\): \[ C \approx 2 \cdot 3.14 \cdot 450 \] This is already in one of the options provided. We can represent it as: \[ C \approx 2 \cdot 3.14 \cdot 450 \] Therefore, the correct response here is: C ≈ 2⋅3.14⋅450

  3. Which formula correctly describes the proportional relationship between the circumference of a circle and the diameter?: The correct formula that describes the relationship between the circumference \(C\) and the diameter \(d\) is: \[ C = \pi d \] Therefore, from the options given, the correct response is: C = πd

To summarize:

  1. 75.36
  2. C ≈ 2⋅3.14⋅450
  3. C = πd