a semicircle has a radius of 20 . what is the approximate perimeter of the semicircle ?
"circumference of a circle = 2 pi * r perimeter of a semicircle = pi * r + 2 r aprox perimiter = 3.14 * 20 + 2 * 20 = 102.8 approximately 102 answer e"
add(divide(circumface(20), const_2), multiply(const_2, 20))