Circles - Radius, Diameter, Area and Circumference

How can you tell when x and y are not directly proportional?

Someone answer asap for ! the following statements are true about the coins calvin and sasha have collected. * calvin and sasha has the same amount of money. * calvin has only quarters. * sasha has dimes, nickels, and pennies * calvin has the same number of quarters as sasha has dimes. * sasha has $1.95 in coins that are not dimes. exactly how many quarters does calvin have?

3.4a=57.8 what is the the value of a