if circles x and y have the same area and circle x has a circumference of 18 π , half of the radius of circle y is :
"x be radius of circle x y be radius of circle y given : pi * x ^ 2 = pi * y ^ 2 also , 2 * pi * x = 18 * pi x = 9 thus y = 9 y / 2 = 4.5 ans : b"
divide(divide(18, const_2), const_2)