Question

Type the correct answer in the box. Use numerals instead of words. If necessary, use / for the fraction bar. A ⁢ B ¯ is parallel to C ⁢ D ¯ , and E ⁢ F ¯ is perpendicular to A ⁢ B ¯ . The number of 90° angles formed by the intersections of E ⁢ F ¯ and the two parallel lines A ⁢ B ¯ and C ⁢ D ¯ is .

Answer 1

In geometry, when two lines are parallel, they never intersect, and when a line is perpendicular to another line, they meet at a right angle, which is 90 degrees. Therefore, in the given problem, the intersection of line EF with lines AB and CD will form two 90-degree angles. This is because line EF is perpendicular to line AB and line AB is parallel to line CD. Therefore, the answer to the question is 2.