2 part question. 1st part: Im givin the redshift of a quasar is .158 and Hubble constant of 65km/s/Mpc. I am asked to find the size of the jet(ly) as projected on the sky which has an angular measure of 15 arc secs. I've looked up ways and on any formulas that could help me but haven't found anything. Does anyone know how to get the size (formula wise). 2nd part: What is the true length in light years if it is pointed along the line of sight but off at an angle of 6 degrees? Now this part I don't understand where to start from. Anything helps thanks.