When two lines are crossed by another line (the Transversal), a pair of angles

• on the inner side of each of those two lines

• but on opposite sides of the transversal

are called Alternate Interior Angles.

c and f are Alternate Interior Angles.

d and e are Alternate Interior Angles.

So there are actually two pairs!

Play with it below (try dragging the points):

• on the inner side of each of those two lines

• but on opposite sides of the transversal

are called Alternate Interior Angles.

c and f are Alternate Interior Angles.

d and e are Alternate Interior Angles.

So there are actually two pairs!

Play with it below (try dragging the points):

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