If the circumference of a circle is 31.4 cm, what is its radius? (Use π = 3.14)

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Question: If the circumference of a circle is 31.4 cm, what is its radius? (Use π = 3.14) (2015)

Options:

Correct Answer: 5 cm

Solution:

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

If the circumference of a circle is 31.4 cm, what is its radius? (Use π = 3.14) (2015)

If the circumference of a circle is 31.4 cm, what is its radius? (Use π = 3.14) (2015)

Step 1: Write down the formula for the circumference of a circle, which is Circumference = 2πr.
Step 2: We know the circumference is 31.4 cm, so we can set up the equation: 31.4 = 2πr.
Step 3: Substitute π with 3.14 in the equation: 31.4 = 2 * 3.14 * r.
Step 4: Calculate 2 * 3.14, which equals 6.28. Now the equation is: 31.4 = 6.28r.
Step 5: To find r, divide both sides of the equation by 6.28: r = 31.4 / 6.28.
Step 6: Calculate 31.4 divided by 6.28, which equals 5. Therefore, the radius r is 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 can be approximated as 3.14 for calculations in this context.