In triangle DEF, side EF is produced to G. If $$\angle DFG$$​ = 110° and EF = DF, then $$\angle DEF$$​ measures:

Correct option is C

Given:

In $$\triangle DEF$$​, EF= DF

If EF is produced to G then $$\angle DFG = 110^o$$​​

Formula Used:

Sum of triangle = $$180^o$$​​

Exterior angle = Sum of interior opposite angles

Solution:

In $$\triangle DEF,$$​ EF =DF then $$\angle D = \angle E$$​    (Angles opposite to equal sides are equal)

If $$\angle EDF = \angle DEF = x$$​ then

​$$\angle EDF +\angle DEF = 110^o$$​      (Exterior angle = Sum of interior opposite angles)

​$$x + x = 110^o$$ 

​$$x= 55^o$$​​

​$$\angle DEF = 55^o$$​​