How do i locate wordpress plugin directory?

I am trying to add a function from plugin 1(wp job manager) to plugin 2(woocommerce).

I have decided to do this by including the php file from plugin 1, however I am unable to locate the file directory. I have used:

include( plugin_dir_path( FILE ) . 'wp-job-manager/includes/class-wp-job-manager-applications.php');

but it returns the following error:

Warning: include(/home/content/p3pnexwpnas05_data02/78/2394078/html/wp-content/themes/listify-child/wp-job-manager/includes/class-wp-job-manager-applications.php): failed to open stream: No such file or directory in /home/content/p3pnexwpnas05_data02/78/2394078/html/wp-content/themes/listify-child/functions.php on line 77

Please advise me as I've been stuck on this issue for really long... Thanks!!!