Alternate interior angles — Grade 8 Math, what it means and where it is taught
Between the parallels, on opposite sides of the transversal. Equal.
Taught in Grade 8 Math.
Where it is taught
What it rests on
Work through these first if this one does not settle.
- Transversal — A line that crosses two or more other lines.
Practise this idea
3 questions in the course bank use Alternate interior angles, in Angle Relationships, How to Write a Proof.
Problem 1
An angle of 48° has an alternate interior partner. Find it.
Worked answer
48
The Z shape gives equal angles
48°
Problem 2
Which pair of angles is not necessarily equal when two parallel lines are cut by a transversal?
- Co-interior angles
- Corresponding angles
- Alternate interior angles
- Vertical angles
Worked answer
Co-interior angles
Co-interior angles are supplementary, not equal
They are only equal in the special case of 90° each
Problem 3
You are given that AB ∥ CD. What angle relationship does a transversal give you?
Worked answer
congruent alternate interior angles
Alternate interior angles are congruent.
Corresponding angles are congruent too.