How can I work out the area of a semi-circle with a diameter of 12cm?

For this question we need to remember that the equation to calculate the area of a circle is pi times the radius squared. The radius of a circle is half it's diameter, therefore the radius of the semi-circle in question is 12/2 = 6 cm. So we'll put this into the original equation to get 3.14 times 6² which will give us an answer of 113.04. However this is not our final answer as the question asks for the area of a semi-circle, which is half that of a full circle, therefore we must divide our answer by two leaving us with an area of 56.52. When reporting the final answer remember the units of area must be squared, giving a final answer of 56.52 cm².