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Co-interior Angles on Parallel Lines

In this section, we will investigate one final pair of angles formed when two parallel lines are intersected by another line (known as a transversal). the below applet shows examples of co-interior angles.

Use the above applet to investigate co-interior angles. In your own words, describe what co-interior angles are.

What do co-interior angles add up to?

PART 1

For each diagram below, decide whether the angles marked are co-interior angles or not.

Which of the above diagrams show co-interior angles?

Select all that apply
  • A
  • B
  • C
  • D
Check my answer (3)

PART 2

Consider the below diagram.

What is the missing marked angle? Justify your answer.