NAME _____________________________PD____ DATE____________
INVESTIGATION: PROPERTIES OF PARALLEL LINES
STEP 1: Copy and paste the following URL into your browser
http://www.mathwarehouse.com/geometry/angle/interactive-transveral-angles.php OR Click
HERE to go to the link.
STEP 2: Click on the DIRECTIONS button located under the “Angles of Parallel Lines and
A Transversal” heading.
STEP 3: Carefully READ the directions for how to move the lines, then click the
DIRECTIONS button again to close the box.
STEP 4: Experiment with moving the parallel lines and the transversal. Roll the mouse over
different angles and observe how the measurements light up.
PART 1: CORRESPONDING ANGLES
Click on the button labeled CORRESPONDING ANGLES located on the right
hand side of the page. Corresponding angles will be color-coded.
A. Locate 2 pairs of corresponding angles and record their measurements:
ANGLE
MEASUREMENT
1a.
1b.
2a.
2b.
B. MOVE the parallel lines and the transversal. Locate 2 pairs of
corresponding angles and record their measurements:
ANGLE
3a.
3b.
4a.
4b.
What do you notice about the corresponding angles?
MEASUREMENT
NAME _____________________________PD____ DATE____________
Compare your results with your partner(s). Make a conjecture based on the
information you collected.
When parallel lines are cut by a transversal, corresponding angles
formed are_________________________.
(CORRESPONDING ANGLES CONJECTURE)
PART 2: ALTERNATE INTERIOR ANGLES
Click on the button labeled ALTERNATE INTERIOR ANGLES located on the
right hand side of the page. Alternate interior angles will be color-coded.
A. Locate 2 pairs of alternate interior angles and record their
measurements:
ANGLE
MEASUREMENT
1a.
1b.
2a.
2b.
B. MOVE the parallel lines and the transversal. Locate 2 pairs of alternate
interior angles and record their measurements:
ANGLE
MEASUREMENT
3a.
3b.
4a.
4b.
What do you notice about the alternate interior angles?
Compare your results with your partner(s). Make a conjecture based on the
information you collected.
NAME _____________________________PD____ DATE____________
When parallel lines are cut by a transversal, alternate interior angles
formed are______________________________.
(ALTERNATE INTERIOR ANGLES CONJECTURE)
PART 3: ALTERNATE EXTERIOR ANGLES
Click on the button labeled ALTERNATE EXTERIOR ANGLES located on the
right hand side of the page. Alternate exterior angles will be color-coded.
A. Locate 2 pairs of alternate exterior angles and record their
measurements:
ANGLE
MEASUREMENT
1a.
1b.
2a.
2b.
B. MOVE the parallel lines and the transversal. Locate 2 pairs of alternate
exterior angles and record their measurements:
ANGLE
MEASUREMENT
3a.
3b.
4a.
4b.
What do you notice about the alternate exterior angles?
Compare your results with your partner(s). Make a conjecture based on the
information you collected.
When parallel lines are cut by a transversal, alternate exterior angles
formed are______________________________.
(ALTERNATE EXTERIOR ANGLES CONJECTURE)
NAME _____________________________PD____ DATE____________
PART 4: SAME-SIDE INTERIOR ANGLES
A. Locate 2 pairs of same-side interior angles and record their
measurements:
ANGLE
MEASUREMENT
1a.
1b.
2a.
2b.
B. MOVE the parallel lines and the transversal. Locate 2 pairs of same-side
interior angles and record their measurements:
ANGLE
MEASUREMENT
3a.
3b.
4a.
4b.
What do you notice about the same-side interior angles?
Compare your results with your partner(s). Make a conjecture based on the
information you collected.
When parallel lines are cut by a transversal, same-side interior angles
formed are______________________________.
(SAME-SIDE INTERIOR ANGLES CONJECTURE)
NAME _____________________________PD____ DATE____________
SUMMARY
Corresponding Angles Conjecture: If two parallel lines are cut by a
transversal, then the corresponding angles are _____________________.
Conversely, ________________________________________________.
Alternate Interior Angles Conjecture: If two parallel lines are cut by a
transversal, then the alternate interior angles are ___________________.
Conversely, ________________________________________________.
Alternate Exterior Angles Conjecture: If two parallel lines are cut by a
transversal, then the alternate exterior angles are __________________.
Conversely, ________________________________________________.
Same-Side Interior Angles Conjecture: If two parallel lines are cut by a
transversal, then the same-side interior angles are __________________.
Conversely, ________________________________________________.
FINAL CHECKS FOR UNDERSTANDING
1
5
9
13
c
10
14
2
3
6
7
11
15
12
16
4
a
8
b
d
Given a // b, name all angles which are congruent to 4. ____________________
Given c // d, name all angles which are congruent to 16.____________________
Given a // b and c // d, name all angles which are congruent to 1._____________
NAME _____________________________PD____ DATE____________
2
120
1
a. m ∠ 1 = ______
REASON:
______________
b. m ∠ 2 = _____
REASON:
______________
a. m ∠ 1 = ______
REASON:
______________
b. m ∠ 2 = _____
REASON:
______________
ALGEBRA: Now, try this one:
(x + 10)º
115º
(2x – 55)º
a. m ∠ 1 = ______
REASON:
______________
b. m ∠ 2 = _____
REASON:
______________