The question asks to calculate the area of a semicircle which is half a circle so the area of a semicircle is half the area of a circle.
Area of a semicircle = area of circle/2 or area of a circle = 2* area of semicircle.
Area of a semicircle = πr2 /2
The diameter is a straight line that runs through the center of the circle from one point on a circle to another. The radius is the line from the centre of the circle to any point on the circle.
Thus, the length of a radius is half the length of the diameter.
Radius = diameter/2 or diameter = 2* radius.
The diameter of the circle is given i.e.12 cm. To calculate the area of a semicircle we must calculate the area of a circle and divide it by 2. The area of a circle = πr2 but the radius is not given. However, it is half the diameter so r = 12 / 2 = 6 cm. Then use it to calculate the area of a circle which is 3.142 * 6 * 6 = 113.112 cm2. We use cm2 as the unit as the radius is measured in cm and it is squared. Then simply divide the area of the circle by 2 to calculate the area of the semicircle i.e. 113.112 / 2 = 56. 556 cm2.