Question

find the circumference. 18 cm

Explanation:

Step1: Identify the formula for circumference

The formula for the circumference \( C \) of a circle when the diameter \( d \) is known is \( C=\pi d \).

Step2: Substitute the given diameter

Here, the diameter \( d = 18\space\text{cm} \). Substituting into the formula, we get \( C=\pi\times18 \). Taking \( \pi\approx3.14 \), we have \( C = 3.14\times18 \).

Step3: Calculate the value

\( 3.14\times18=56.52\space\text{cm} \) (or if we use \( \pi=\frac{22}{7} \), \( C=\frac{22}{7}\times18=\frac{396}{7}\approx56.57\space\text{cm} \), but using \( \pi = 3.14 \) is common for such problems).

Answer:

The circumference of the circle is approximately \( 56.52\space\text{cm} \) (or \( \frac{396}{7}\space\text{cm}\approx56.57\space\text{cm} \) if using \( \pi=\frac{22}{7} \)).