NAME_____________________________________ PERIOD_____ DATE__________
Properties of Parallel Lines Investigation
Go to the following website:
http://www.mathwarehouse.com/geometry/angle/interactive-transveral-angles.php
Click on the DIRECTIONS button located under the “Angles of Parallel Lines and A
Transversal” heading. Read the directions for how to move the lines then click the
DIRECTIONS button again to close the box.
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.
Locate 2 pairs of corresponding angles and record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Move the parallel lines and the transversal. Locate 2 pairs of corresponding angles and
record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Make a conjecture based on the information you collected.
When parallel lines are cut by a transversal,
corresponding angles formed are__________________________.
NAME_____________________________________ PERIOD_____ DATE__________
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.
Locate 2 pairs of alternate interior angles and record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Move the parallel lines and the transversal. Locate 2 pairs of alternate interior angles
and record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Make a conjecture based on the information you collected.
When parallel lines are cut by a transversal,
alternate interior angles formed are__________________________.
NAME_____________________________________ PERIOD_____ DATE__________
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.
Locate 2 pairs of alternate exterior angles and record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Move the parallel lines and the transversal. Locate 2 pairs of alternate exterior angles
and record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Make a conjecture based on the information you collected.
When parallel lines are cut by a transversal,
alternate exterior angles formed are__________________________.
NAME_____________________________________ PERIOD_____ DATE__________
PART 3: SAME SIDE INTERIOR ANGLES
Locate 2 pairs of same side interior angles and record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Move the parallel lines and the transversal. Locate 2 pairs of same side interior angles
and record their measurements:
Angle Pair Names
Measurement
1
2
1
2
Make a conjecture based on the information you collected.
When parallel lines are cut by a transversal, same side interior angles
formed are___________________________.
NAME_____________________________________ PERIOD_____ DATE__________
Properties of Parallel lines
DEFINITION OF PARALLEL LINES
Two or more lines are parallel if and only if
_____________________________________________________________.
Symbols showing that line a is parallel to line b:
Conjecture: If two parallel lines are cut by a transversal, then the
corresponding angles which are formed are ___________________.
Conversely,
_____________________________________________________________
_____________________________________________________________.
Conjecture: If two parallel lines are cut by a transversal, then the alternate
interior angles which are formed are ______________________.
Conversely,
_____________________________________________________________
_____________________________________________________________.
Conjecture: If two parallel lines are cut by a transversal, then the alternate
exterior angles which are formed are _______________________.
Conversely,
_____________________________________________________________
_____________________________________________________________.
Conjecture: If two parallel lines are cut by a transversal, then the same-side
interior angles which are formed are ____________________________.
Conversely,
_____________________________________________________________
_____________________________________________________________.
NAME_____________________________________ PERIOD_____ DATE__________
1
5
9
13
2
3
6
10
14
7
11
15
c
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.
EXAMPLE
(x + 10)º
115º
(2x – 55)º
HW: Textbook Pgs. 118-119: # 1-7 all, 11-17 all, 23, 25.