Question

∠C and ​ ∠D ​ are vertical angles with  m∠C=−x+26 and  m∠D=2x−10 .   What is m∠D ?

Answer 1

∠C and ​ ∠D are equal.

so −x+26 =2x-10

-3x=-36

x=36/3

x=12°

∠D= 2x-10

put value of x here

∠D=24-10

∠D=14°

Answer 2

vertical angles are made by two intersecting lines .and they are always equal
∠C and ​ ∠D are equal.
so −x+26 =2x-10
-3x=-36
x=36/3
x=12°

∠D= 2x-10
put value of x here
∠D=24-10
∠D=14°