FTCE General Knowledge Math Practice Test

How would you express the circumference of a circle in terms of its radius?

1. 2(3.14)(r)

2. (3.14)r^2

3. bh

4. 1/3Bh

The correct answer is: 2(3.14)(r)

The circumference of a circle can be expressed using the formula \( C = 2\pi r \), where \( C \) represents the circumference, \( r \) is the radius of the circle, and \( \pi \) (approximately 3.14) is a mathematical constant representing the ratio of the circumference to the diameter of a circle. In the correct answer, the expression \( 2(3.14)(r) \) effectively represents \( 2\pi r \), substituting the value of \( \pi \) with 3.14, which provides a way to calculate the circumference using the radius. This conveys the essential relationship between the radius and the distance around the circle. The other options presented either relate to different geometric concepts or provide formulas that do not pertain to the circumference of a circle. Specifically, \( (3.14)r^2 \) appears to be the area formula for a circle rather than the circumference. The terms \( bh \) and \( 1/3Bh \) are formulas for the area of a rectangle and the volume of a prism, respectively, and do not apply to circular geometry. Thus, the only appropriate expression for the circumference in terms of the radius