Line ab intersects line df. which statement shows that the two lines are perpendicular? line ab and line df are on the same plane. line ab and line df intersect only once. line ab and line df intersect at a 90° angle. line ab and line df intersect at a 180° angle.

Line AB and line AD intersect at a 90° angle

Explanation:
Two lines are said to be perpendicular if the angle between the two lines is 90 degrees.
If the angle between the two lines is 180, the two lines are said to be supplementary angles
The first and second options do not imply that the lines are perpendicular as the angle formed between them could be less or more that 90°.

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