If the circumference of a circle is 31.4 cm, what is the radius? (2020) 2020

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Question: If the circumference of a circle is 31.4 cm, what is the radius? (2020) 2020

Options:

Correct Answer: 5 cm

Exam Year: 2020

Solution:

Circumference = 2πr. Therefore, r = Circumference / (2π) = 31.4 cm / (2 * 3.14) = 5 cm.

If the circumference of a circle is 31.4 cm, what is the radius? (2020) 2020

If the circumference of a circle is 31.4 cm, what is the radius? (2020) 2020

Step 1: Understand that the circumference of a circle is given by the formula: Circumference = 2πr, where r is the radius.
Step 2: We know the circumference is 31.4 cm. So we can set up the equation: 31.4 cm = 2πr.
Step 3: To find the radius (r), we need to rearrange the formula. We can do this by dividing both sides by 2π: r = Circumference / (2π).
Step 4: Substitute the value of the circumference into the equation: r = 31.4 cm / (2 * π).
Step 5: Use the approximate value of π, which is 3.14. So, calculate 2 * 3.14 = 6.28.
Step 6: Now, divide 31.4 cm by 6.28: r = 31.4 cm / 6.28.
Step 7: Perform the division: r = 5 cm.

Circumference of a Circle – The circumference of a circle is calculated using the formula C = 2πr, where C is the circumference and r is the radius.
Solving for Radius – To find the radius from the circumference, rearranging the formula to r = C / (2π) is necessary.
Use of π – Understanding that π is approximately 3.14 is crucial for accurate calculations.