Answer:
[tex]C\text{ = }\pi r[/tex]Explanation:
Formula for calculating the circumference of a circle is expressed as;
[tex]C\text{ = 2}\pi r[/tex]r is the radius
Since a semi-circle is half of a circle, then the circumference will be half of cirumference of a circle as shown;
[tex]\begin{gathered} C\text{ = }\frac{2\pi r}{2} \\ C\text{ = }\pi r \end{gathered}[/tex]This gives the circumference of s semicircle where r is the radius of the semi circle