[Antennaware] cutting phasing lines

[Allan Greening]

If using EG213 coax how do I WORK OUT
1 If using 84 es 71 degree phasing lines how do i find the length.
2 how do I find the cutting frequency
 on 1.850 Mhz.. for a pair of 1/4 wave verticals  90 ft top loaded??
tu es 73 vk3pa Allan