Since ∠3 and ∠5 are vertical angles, we know that m∠3 = m∠5. Given that m∠3 = 67°, we can conclude that m∠5 = 67° as well.
Next, since ∠4 is a supplementary angle with ∠5, we know that the sum of the measures of these two angles is 180°. Therefore, we can write the equation:
m∠4 + m∠5 = 180°
Substituting the value of m∠5 into the equation:
m∠4 + 67° = 180°
So, the equation you can write to solve for m∠4 is:
m∠4 + 67° = 180°