∠4 = 11
Step-by-step explanation:
In this question we can use the exterior angle theorem. This means that the two other angles that aren't adjacent to ∠4 are equal to ∠4 when added together. If you add ∠1 and ∠2 together, you will get ∠4.
[tex]8x+9+4x+14=13x+12[/tex]
Combine like terms.
[tex]12x+23=13x+12[/tex]
Subtract 13x from both sides.
[tex]x+23=12[/tex]
Subtract 12 from both sides.
∠4 = 11
