PHP - How to getting a random coordinate inside a polygon using php

I wan to get a longitude and latitude randomly from polygon coordinates type. This my polygon coordinates.

$coord = [ [ [ 101.47910154600004, -0.634376845999952, 0.0 ], [ 101.47886382700005, -0.634420904999956, 0.0 ], [ 101.47742251100004, -0.635152318999928, 0.0 ], [ 101.47703529200004, -0.63719597599993, 0.0 ], [ 101.47745477900008, -0.639142828999979, 0.0 ], [ 101.47818619300006, -0.642391167999961, 0.0 ], [ 101.47916499800004, -0.645886896999968, 0.0 ], [ 101.47990493600008, -0.648074361999932, 0.0 ], [ 101.47968326400007, -0.648103958999968, 0.0 ], [ 101.47908902100005, -0.648195380999937, 0.0 ], [ 101.47812909000004, -0.648439172999929, 0.0 ], [ 101.47710821200008, -0.648896282999942, 0.0 ], [ 101.47642254700008, -0.649475288999952, 0.0 ], [ 101.47566069700008, -0.649825739999926, 0.0 ], [ 101.47508169100007, -0.649993346999963, 0.0 ], [ 101.47421276500006, -0.649997334999966, 0.0 ], [ 101.47328380400006, -0.649702647999959, 0.0 ], [ 101.47298822600004, -0.645373874999962, 0.0 ], [ 101.47251554700006, -0.641172277999942, 0.0 ], [ 101.47252644800005, -0.640984085999946, 0.0 ], [ 101.47267310700005, -0.638546278999968, 0.0 ], [ 101.47351342600007, -0.634659800999941, 0.0 ], [ 101.47493146500005, -0.632821601999979, 0.0 ], [ 101.47720723700007, -0.631317749999937, 0.0 ], [ 101.47791055700009, -0.632653291999929, 0.0 ], [ 101.47879716500006, -0.633949211999948, 0.0 ], [ 101.47910154600004, -0.634376845999952, 0.0 ] ] ];