m∠FCE =25º
1) Since the measure of ∠DCF = 115º and ∠DCE = 90º then by the Angle Addition postulate we can state that
∠DCF = ∠DCE +∠FCE Plugging into that the given values
115º = 90º + ∠FCE Subtracting 90º from both sides
115-90=∠FCE
25º =∠FCE
2) Then the measure of ∠FCE is 25º
