When two lines intersect, they create two pairs of vertically opposite angles. The angles are often labeled as follows:
- ∠A and ∠C are vertically opposite angles.
- ∠B and ∠D are vertically opposite angles.
Since vertically opposite angles are equal, we have:
\[ m∠A = m∠C \]
Given that \( m∠C = 75° \), we can find \( m∠A \):
[ m∠A = m∠C = 75° \