Ontario Mathematics Proficiency Practice Test

To determine the circumference of a circle, the formula used is \( C = 2\pi r \), where \( C \) represents the circumference and \( r \) is the radius of the circle. Given that the radius of the circle is 7 cm, we can substitute this value into the formula.

First, calculate \( 2 \times 7 \), which equals 14. Then, multiply this result by \( \pi \), which is approximated as 3.14 in this case:

\[ C = 2 \times 3.14 \times 7 \]

\[ C = 14 \times 3.14 \]

\[ C = 43.96 \, \text{cm} \]

This calculation shows that the circumference of the circle with a radius of 7 cm is indeed 43.96 cm. The method illustrates how multiplying the diameter (which is twice the radius) by the value of \( \pi \) gives the correct measurement of the circle's perimeter.