<span>When two lines are crossed by a transversal, the lines are </span>parallel if <span>the </span>Alternate Interior Angles are equal<span>. </span><span>Alternate Interior Angles in the diagram are 1 and 5; 4 and 8; 2 and 6 and 3 and 7. If lines a and b are parallel, then angle 1 must equal angle 5. If that's the case then </span><span>2x+30 equals 5x ‒ 45 </span><span>Solving 2x+30 = 5x ‒ 45 3x = 75 x = 25 So, when x = 25, the lines are parallel.
