Geometry Part I
3.8 - Slopes of Parallel and Perpendicular Lines
pg. 201 - 204 Even Solutions
10.
m1 
5 1
4
 4
 2  3 1
m2 
22 4

4
0 1
1
Since the two lines have the same slope, they are parallel.
14.
1
y  0  ( x  6)
3
18.
m1 
y
40
4

 1
22 4
1
x2
3
m2 
24 6

1
33 6
Since the slopes of the two lines have opposite signs and are reciprocals of each other,
the two lines are perpendicular.
24.
y  7x  6 
y  7x  8 
30.
m AB 
m AD
36.
y  7x  6
The slopes are not equal, so the lines are NOT parallel.
y  7 x  8
42 2
74 3
57 2 2

mBC 

 3
mCD 


30 3
2  3 1
1 2  3 3
52
3


 3
Since opposite sides slopes are equal, they are parallel.
1  0 1
y  x  7 
y  x  20 
y  x  7
y  x  20
Since the slopes are opposite reciprocals, they are
perpendicular.
42.
mGH 
82 6
 3
53 2
m HK 
10  8 2
2


05 5
5
mGK 
10  2 8
8


03 3
3
Since none of the slopes are opposite reciprocals, they are not perpendicular, so there
cannot be a right angle.
10
46.
Since the slope from R to Q is down 1, over 4,
S2
8
6
if you go the same down 1, over 4 from P,
R
P
2
S1 should be placed at (6, 1)
OR
-10 -8
-6
-4
-2
2
-2
Since the slope from P to R is up 3, over 1,
if you go the same up 3, over 1 from Q,
52.
P = s + s + s + s = 4s
A = s2
A = (5)2
-4
-6
-8
-10
S2 should be placed at (8, 7)
20 = 4s
5=s
Area = 25 ft. sq.
Q
4
S1
4
6
8
10