Were is the fourth badge on emerald version?

go to firy fiery firey path to meteor falls then go back through firey path and you will notice team magmas not there go to the path they were blocking and go up the cable car defeat team magma and go down jagged path (notice that AA magma guy is there wierd huh) go to lavaridge gym defeat it and may/brendon will come out of the house and let you see in the dessert now go defeat your dad.