To find the circumference of a circle when the diameter is given, we use the formula:
[tex]\[ C = \pi \times d \][/tex]
where [tex]\( C \)[/tex] represents the circumference, [tex]\( \pi \)[/tex] is a mathematical constant approximately equal to [tex]\( 3.14159 \)[/tex], and [tex]\( d \)[/tex] is the diameter.
Given that the diameter ([tex]\( d \)[/tex]) of the circle is [tex]\( 4 \)[/tex] cm, we can plug this value into the formula:
[tex]\[ C = \pi \times 4 \][/tex]
Thus, the equation that can be used to find the circumference of the circle is:
[tex]\[ C = \pi \times 4 \][/tex]
