Create a cumulative line chart based on two tables

Hi there,

Very new to PowerBI tools, currently a bit stuck on this issue. 

I have two tables

• Tasks table with a Proposals (another table) foreign key
  • Has two notable columns: Start Date and End Date
• Resources Table
  • A resource with a total cost

I've joined the two tables based on a TaskID and the Resource table that has a foreign key linked to Tasks, so the structure is similar to this, with other columns as well.

There may be multiple tasks involved in a proposal, is there a way to do a running cumulative line chart where it may increase on a per day basis so it can produce something like this below?

Running total costs

Thanks!