Question

What is the value of X. Triangles 39 is one angle and 102 is the other angle

Answer 1

All three angles on a triangle always equal 180°.
Example: 100°+40°+40°=180°

102+39=141°
180-141=39°
x = 39°

Answer 2

When you add up all the angles it should equal to 180 so 180-102=78 then 78-39=39 so x=39