Acircle has a diameter of 26 cm. what is it's circumference?

Me because some of question i don’t understand

You so much whoever answers with accuracy •the parent function of the graph of f(x) is the square root function, which was reflected across the x-axis. which of the following is the equation of f(x)?

My final challenge question of the day! i have no tests, nothing to do this for, it is simply giving away free points for a you tube video! so 50 free points for answering the most simple question ever! here is the key to getting brainiest for this question. answer in under 50 seconds. you think you can do it. i think you can. here is the question: 1x2= i know! easiest question ever! and yes! if you answer this question, you will be on you so come on and get the free 50 while you can!