FTCE General Knowledge Math Practice Test

Disable ads (and more) with a membership for a one time $4.99 payment

Prepare for the FTCE General Knowledge Math Test with our comprehensive quiz. Study using flashcards and multiple-choice questions, all with detailed hints and explanations. Get ready to excel on your exam!

Practice this question and more.

How is the circumference of a circle calculated?

C = 2πr
C = πd
C = 2r
C = πr²

The correct answer is: C = 2πr

The formula for calculating the circumference of a circle can indeed be represented as C = 2πr. This formula directly relates the circumference (C) to the radius (r) of the circle, where π (pi) is a mathematical constant approximately equal to 3.14159. In this formula, multiplying the radius by 2 gives the diameter of the circle, and then by multiplying by π, you effectively find the perimeter or boundary length of the circle. This relationship illustrates how the circumference is fundamentally tied to the circle's radius. Other choices provided do not accurately calculate the circumference. For example, C = πd is correct too but uses the diameter instead of the radius. C = 2r does not involve π, which is essential in calculating the circumference. Finally, C = πr² represents the formula for the area of a circle, not the circumference. Thus, C = 2πr correctly conveys the relationship needed to find the circumference using the radius.