Let’s go step by step to fill in the blanks for both
Alternate Interior Angles and
Alternate Exterior Angles.
---
How to find Alternate INTERIOR Angles:
#### Step 1:
> Find the _______________ line ___
*Note: A transversal crosses at least two lines.*
✔ The key word here is
transversal — it’s the line that cuts across the other two lines. In the diagram, line
c is the one crossing lines a and b.
→ So:
Find the _transversal_ line _c_
*(We’ll use “c” because in all diagrams, line c is the slanted one cutting through a and b.)*
---
#### Step 2:
> Since we’re looking for INterior angles, look at the angles _______________ the other two lines. □__ □__ □__ □__ .
✔ “Interior” means *between* the two lines being crossed (lines a and b). So we look at angles between them.
In the diagram, angles between lines a and b are:
3, 4, 5, 6
→ So:
look at the angles _between_ the other two lines. □3 □4 □5 □6
---
#### Step 3:
> An ALTERNATE interior angle pair are 2 angles that are _______________ of the transversal. (There are 2 pairs of alternate interior angles.) □__ and □__, □__ and □__.
✔ “Alternate” means on *opposite sides* of the transversal. And they must be *interior* (between the two lines).
So:
- Angle 3 and angle 6 → opposite sides of transversal c, both inside →
✔
- Angle 4 and angle 5 → opposite sides of transversal c, both inside →
✔
→ So:
angles that are _on opposite sides_ of the transversal. □3 and □6, □4 and □5
---
🔹 How to find Alternate EXTERIOR Angles:
#### Step 1:
> Find the _______________ line ___
*Note: A transversal crosses at least two lines.*
Same as before — the transversal is line
c.
→ So:
Find the _transversal_ line _c_
---
#### Step 2:
> Since we’re looking for EXterior angles, look at the angles _______________ the other two lines. □__ □__ □__ □__ .
✔ “Exterior” means *outside* the two lines being crossed (a and b). So angles not between them.
In the diagram, exterior angles are:
1, 2, 7, 8
→ So:
look at the angles _outside_ the other two lines. □1 □2 □7 □8
---
#### Step 3:
> An ALTERNATE exterior angle pair are 2 angles that are _______________ of the transversal. There are 2 pairs of alternate exterior angles: □__ and □__, □__ and □__.
✔ Again, “alternate” = opposite sides of transversal. “Exterior” = outside the two lines.
So:
- Angle 1 and angle 8 → opposite sides of transversal c, both outside →
✔
- Angle 2 and angle 7 → opposite sides of transversal c, both outside →
✔
→ So:
angles that are _on opposite sides_ of the transversal. □1 and □8, □2 and □7
---
## Final Answer:
Left Column (Alternate Interior Angles):
1. Find the
transversal line
c
2. Since we’re looking for INterior angles, look at the angles
between the other two lines. □
3 □
4 □
5 □
6
3. An ALTERNATE interior angle pair are 2 angles that are
on opposite sides of the transversal. □
3 and □
6, □
4 and □
5
---
Right Column (Alternate Exterior Angles):
1. Find the
transversal line
c
2. Since we’re looking for EXterior angles, look at the angles
outside the other two lines. □
1 □
2 □
7 □
8
3. An ALTERNATE exterior angle pair are 2 angles that are
on opposite sides of the transversal. □
1 and □
8, □
2 and □
7
Parent Tip: Review the logic above to help your child master the concept of interior exterior angles worksheet.
