How do i find the circumference and area of a circle

You’re giving a cube with a length of 2.5 cm and a width of 2.5 cm and a high of 2.5 cm you place it on a scale and it is 295 g calculate the density

Determine if the equation defines y as a function of x: 2xy = 1. yes o no

Can you me with this question? i'll reward *30 points i just need with this one question so that i could solve the others. * edit: i originally set up the question to reward 30 points, but for some reason i can only reward 15. if you don't get 30, then i'm sorry. i'm still kind of new to this site