Can someone pls help with this question and could you show working with the answer.

Acircle has a circumference of 28.36 units what is the diameter of the circle

Which of the following describes the graph of y--4x-36 compared to the parent square root function? stretched by a factor of 2, reflected over the x-axis, and translated 9 units right stretched by a factor of 2, reflected over the x-axis, and translated 9 units left stretched by a factor of 2, reflected over the y-axis, and translated 9 units right stretched by a factor of 2, reflected over the y-axis, and translated 9 units left save and exit next submit

Iknow its nothing to do with education, but what type of thing should i wrote here? ? : ) its for mcdonald's btw.