Download If //, corresp. ∠s ≅ If //, alt. int. ∠s ≅

Geom 09_28_16 sect 2_5
September 28, 2016
warm-up:
Identify the type of angles.
1.
∠C and ∠G
2.
∠D and ∠E
3.
∠A and ∠H
4.
∠D and ∠F
5.
∠D and ∠A
6.
∠H and ∠F
Geometry 2.5 Use Parallel Lines and Transversals
When sunlight enters a drop of rain, different colors of light leave the drop at
different angles.
Goal: I can classify and calculate angles formed by
parallel lines and transversals [G.CO.9]
Tiling Activity
GOAL: use angles formed by parallel lines and transversals.
Opening Activity: -- EXPLORE PARALLEL LINES (G-CO.9)
Step 1: Draw a pair of parallel lines cut by a
nonperpendicular transversal on lined paper.
Label the angles as shown
Step 2: Trace angle 1 onto tracing paper. Move
the tracing paper around your picture to find
all angles that are congruent to angle 1.
Step 3: Trace angle 3 onto tracing paper.
Move the tracing paper around your picture to
find all angles that are congruent to angle 3.
Step 4: List all pairs of congruent angles.
∠1 ≅ _______ ≅ ________ ≅ ________
∠3 ≅ _______ ≅ ________ ≅ ________
Corresponding Angles
Alternate Interior Angles
If 2 parallel lines are cut by a transversal,
then corresponding angles are congruent.
If //, corresp. ∠s ≅
If 2 parallel lines are cut by a transversal,
then alternate interior angles are congruent.
If //, alt. int. ∠s ≅
Back to table
Back to table
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Geom 09_28_16 sect 2_5
September 28, 2016
Consecutive Interior
(Same-Side Interior)
Angles:
Alternate Exterior Angles
If 2 parallel lines are cut by a transversal,
then alternate exterior angles are congruent.
If //, alt. ext. ∠s ≅
Back to table
If 2 parallel lines are cut by a transversal, then
consecutive (same-side) interior angles are supplementary.
If //, consecutive int. ∠s supplementary
Back to table
Find the measure of the numbered angles. Justify your answer.
Justify your answer.
6.
100˚
1
2
7.
3
4
8. Solve for x and y.
9. Solve for x.
135o
y˚
(x – 30)o
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Geom 09_28_16 sect 2_5
September 28, 2016
Summary
If //, corresp. ∠s ≅
If //, alt. ext. ∠s ≅
If //, alt. int. ∠s ≅
If //, consecutive int. ∠s are supplementary
Vert. ∠s ≅
Linear Pairs are supplementary
Assignment:
2.5 worksheet
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