Def: line that do not intersect.

Illustration:

Notation: l || m AB || CD

lm

A

B

C

D

Examples of Parallel Lines

• Hardwood Floor

• Opposite sides of windows, desks, etc.

• Parking slots in parking lot

• Parallel Parking

Examples of Parallel Lines

• LINE A

LINE B

HERE LINE A and LINE B Are PARALLEL

Def: Lines that intersect to form a right angle.

Illustration:

Notation: m n

Key Fact: 4 right angles are formed.

m

n

Ex. of Perpendicular Lines• Window panes : The Window Panes

are • PERPENDICULAR to each other

Def: a line that intersects two lines at different points

Illustration:

t

Two angles that are opposite angles.

1 2

3 4

5 6

7 8

t

1 = 42 = 35 = 86 = 7

Find the measures of the missing angles

125

?

?

55

t

55

125

Two angles that form a line (sum=180)

1 2

3 4

5 6

7 8

t

5+6=1806+8=1808+7=1807+5=180

1+2=1802+4=1804+3=1803+1=180

Find the measures of the missing angles

? 72

?

t

108

108 180 - 72

Two angles that occupy corresponding positions.

Top Left

t

Top Left

Top Right

Top Right

Bottom Right

Bottom Right

Bottom Left

Bottom Left

1 = 52 = 63 = 74 = 8

1 2

3 4

5 6

7 8

Find the measures of the missing angles

145

?

t

35

145

Two angles that lie between parallel lines on opposite sides of the transversal t

3 = 64 = 5

1 2

3 4

5 6

7 8

Find the measures of the missing angles

82

?

t

98 82

Two angles that lie outside parallel lines on opposite sides of the transversal t

2 = 71 = 8

1 2

3 4

5 6

7 8

Find the measures of the missing angles

120

?

t

60 120

Two angles that lie between parallel lines on the same sides of the transversal t

3 +5 = 1804 +6 = 180

1 2

3 4

5 6

7 8

Find the measures of the missing angles

?

t

135

45

180 - 135

THANK YOU