You can answer people's questions by clicking on their question. If there question is not clear you can ask them about it. If you have a question then you can click on the ask question button on the homepage. If your answer is not clear someone can report it and it will erase it but you still get the points. If you plagiarize or do something else like that you can get a warning if you get multiple warnings then your account will be erased if your question is not clear then someone can ask you about it and then you can either answer them back or ignore it. You want to get more points and you get points by answering questions. (Hope this helps)
, you can write it in terms of its diameter like this: 
