maths teacher: a semicircle has a diameter of 20cm work out the perimeter of the semicircle take the value of pi to be 3.14
Perimeter = 1/2 of circumference + diameter
= 1/2 * 2 * pi * r + diameter
= 1/2 * 2 * 3.14 * 10 + 20 cm
and you can finish it.
