Filtered Count from Another Table

The relationship will work.  Just many to many can lead to ambiguous models.  Anyhow, here's how I approached  this one:

1. You are going to need a data table that will work as filter for Incidents and Orders:

make sure to use fields from that table as your slicers, filters, ect.

Then write a measure for Pending Incidents:

Pending Incidents = CALCULATE(COUNTROWS(Incidents),Incidents[Status]="Pending")

Then one for Pending and Service request from the Orders table:

Pending and Service Request = CALCULATE(COUNTROWS(Orders),Filter(Orders,Orders[Status]="Pending" && Orders[Type] = "Service Request"))

Then one last one to divide them out:

Pending Incidents divided by Pending and Service = 
DIVIDE([Pending Incidents], [Pending and Service Request])

Here's the final table. I cannot for life of me find the combo chart though: