So you question is most likely about a triangle DEF with the 3 angles being named D, E, F. The triangle would look something like the image attached below.
If that is what is being asked then i need more info to answer but
By Definition it would be 180 degrees.
There are 540 degrees total in the interior angles of a regular pentagon.
Just so you know, the total degrees of interior angles goes up by 180 degrees.
A triangle is 180 degrees, a quadrilateral 360, and a pentagon 540.