TRANSVERSAL:
A line which intersects two distinct lines in a plane in exactly two points, is called transversal.
A line which intersects two or more given lines in a plane at different points is called a transversal to the given lines.
When a transversal cuts two lines, 8 angles are formed.
This is because at each intersection 4 angles are formed.
Corresponding Angles:
Two angles are said to be a pair of corresponding angles.
If i. They are on the same side of the transversal
ii. One is an interior angle and the other is an exterior angle
iii. They are not adjacent angles.
(1,5), (2, 6) ; (4, 8) ; (3, 7 )
Alternate Interior Angles:
Two angles are said to be a pair of alternate interior angles.
If i) Both are interior angles
They are on either side of the transversal.
They are not adjacent angles.
Alternate Exterior Angles:
Two angles are said to be a pair of alternate exterior angles. If i) Both are exterior angles
They are on either side of the transversal.
They are not adjacent angles.
Co interior angles:-
Two angles are interior and one side of the transversal
Co exterior angles:-
Two angles are exterior and one side of the transversal
When a transversal intersects two parallel lines, then
- Pairs of interior alternate angles are equal .
- Pairs of exterior alternate angles are equal
- Pairs of corresponding angles are equal
- The sum of the interior or exterior angles on the same side of the transversal is
- Pairs of co-interior angles are supplementary.