A student writes an incorrect step while checking if the sum of the measures of the two remote interior angles of triangle ABC below is equal to the measure of the exterior angle. In which step did the student first make a mistake and how can it be corrected?
1) Step 1; it should be mcm +men+mzo = 90 degrees (corresponding angles)
2) Step 1; it should be mzm + men + mco = 90 degrees (adjacent angles)
3) Step 2; it should be mzo + m²p = 180 degrees (alternate exterior angles)
4) Step 2; it should be mzo+map = 180 degrees (supplementary angles)
