calculations check for a transmission line in cadence spectre

hi guys,

as above, can i assume that if i want a quarter wavelength line i can simply take 0.25*2*pi/beta(=2633.97)? if say my length ends up to be 500um for example, and the pdk only allows one line to be max of 180um, can i cascade them in series to get the total length required? eg. 180um + 180um + 140um with the same characteristic impedance of 50ohm each.

as for the characteristic impedance, i assume i can do it by sqrt( total hf inductance/ total capacitance) right? or is it the impedance (real part)?

help or advice is appreciated. thanks!

best regards,
natnoraa