Answer:
75 Degrees
Explanation:
We know that all the angles of a triangle add up to 180.
We also know the each angle of triangle DEF in terms of variables
All we have to do is add the 3 angles which equal a total of 180 Degrees.
Angle D+E+F = 180 Degrees
(5+x) + (6+4x) + (4x) = 180
9x + 11 = 180
9x = 169
x = 18.8 Degrees
Angle F is 4x so it is 4(18.8) = 75 Degrees
This is what i got, I"m not sure what else im supposed to solve for. The multiple choice doesnt make sense.