Perimeter and the area of a semicircle
Perimeter of a semicircle
Remember that the perimeter is the distance round the outside.
The perimeter of a semicircle is half of the circumference plus the diameter.
\(Circumference\, of\, circle=\pi d=\pi\,\times 8=25.12cm\)
\(Half\, of\, circumference = 12.56cm\)
\(Perimeter = 12.56+8=20.56cm \)
Area of a semicircle
A semicircle is half of a circle. The area is half the area of a circle.
For this semicircle:
\(A = \frac{1}{2} \pi r^{2}\)
\( = \frac{1}{2}\times \pi \times 4 \times 4\)
\(=25.13cm^{2}\)
