Answer:
25 degrees
Step-by-step explanation:
The value of an exterior angle is the difference between the two arcs that it forms divide by two. Therefore:
[tex]x+10=\dfrac{146-(6x+6)}{2}[/tex]
Multiply both sides by 2:
[tex]2x+20=146-6x-6[/tex]
Move all of the x's to one side:
[tex]8x+20=146-6[/tex]
Combine all of the constants on the other side:
[tex]8x=120[/tex]
Divide both sides by 8:
[tex]x=15[/tex]
Therefore, ECB=x+10=15+10=25 degrees.
Hope this helps!
