Instructions:Type the correct answer in the box. Use numerals instead of words. If necessary, use / for the fraction bar.
AB is parallel to CD, and EF is perpendicular to AB
The number of 90° angles formed by the intersections of Ef and the two parallel lines AB and CD is ____
AB is parallel to CD, and EF is perpendicular to AB
The number of 90° angles formed by the intersections of Ef and the two parallel lines AB and CD is ____