If the circumference of a circle is 31.4 units, what is its radius? (Use π = 3.1

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Question: If the circumference of a circle is 31.4 units, what is its radius? (Use π = 3.14) (2020)

Options:

Correct Answer: 5

Exam Year: 2020

Solution:

Circumference = 2πr. Setting 31.4 = 2 × 3.14 × r gives r = 5 units.

If the circumference of a circle is 31.4 units, what is its radius? (Use π = 3.14) (2020)

If the circumference of a circle is 31.4 units, what is its radius? (Use π = 3.14) (2020)

Step 1: Write down the formula for the circumference of a circle, which is Circumference = 2πr.
Step 2: Substitute the value of the circumference (31.4) into the formula: 31.4 = 2 × 3.14 × r.
Step 3: Calculate 2 × 3.14, which equals 6.28.
Step 4: Now the equation looks like this: 31.4 = 6.28 × r.
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.
Step 7: Therefore, the radius (r) is 5 units.

Circumference of a Circle – The relationship between the circumference, radius, and π in a circle, expressed as C = 2πr.
Substitution and Algebraic Manipulation – The ability to substitute known values into an equation and solve for the unknown variable.