How does the equation change when the radius changes? Unlike h and k, why is r always positive?

Figure abcd is a parallelogram. if point c lies on the line x = 2, what is the y-value of point c

Find the equation of the trend line (line of best fit). show your work i'm using the points (34,76) (42,91)

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.