A semicircle is a half circle. It is created by drawing a straight line, called the **diameter**, that cuts a circle exactly in half. One half of the circle, along with the diameter, forms the **semicircle**.

The **diameter **is the base of the semicircle and the arc of the circle forms the curved edge of the semicircle.

For example, if the radius of a circle is 5 units, the diameter would be 10 units, and the semicircle would have a radius of 5 units, a diameter of 10 units, and a circumference (or perimeter) of Ï€(5) = 3.14 * 5 = 15.7 units.

It’s worth noting that the area of a semicircle is (Ï€*r^2)/2 where r is the radius of the semicircle.