Answers to Homework 2) 1:14) 5:16) 6 to 5 8) 11 to 1210) 11/1712) 6:5:12 14) 6:11:1716) 5:318) 20:17...
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Transcript of Answers to Homework 2) 1:14) 5:16) 6 to 5 8) 11 to 1210) 11/1712) 6:5:12 14) 6:11:1716) 5:318) 20:17...
Answers to Homework
2) 1:1 4) 5:1 6) 6 to 5
8) 11 to 12 10) 11/17 12) 6:5:12
14) 6:11:17 16) 5:3 18) 20:17
20) 1:5 22) 2d/5c 24) 40,50
26) 45,60,75 28) 67.5,67.5,45
30) 32,44,56
7-2 Properties of Proportions
Proportion = 2 equal ratios
same as
cross multiply
swap
reciprocal
add bottom #
then
ad bca c
b d
a c a c
b d b d
b d
a c
a b
c d
a b c d
b d
Example
First
Outer
Inner
Last
2 22 1 2 4 2 8x x x x x x
1 4
2 2
x x
x x
( 1)( 2) ( 2)( 4)x x x x
2 22 2 8x x x x 2 2 8x x 2 8x
6x
Try On Own (both answers are fractions)
1)
2)
Answers:
1) x = 10/3
2) x = -20/3
2
5
x x
x x
5
2 4
x x
x x
Example
A
B
CDE
AB ED
BC DC
What else do you know?AB BC AC ED DC EC
Given ED = 2, DC = 6, and AB = 3Find BC, AC, and EC.
3
62
EC = 2 + 6 = 8
3 2
6BC 2BC = 18, BC = 9
AC = 3 + 9 = 12
Example
A
B
CDE
AB ED
BC DC
Given AB = 12, BC = 4, and EC = 20Find ED, DC, and AC.
12
4
20
AC = 12 + 4 = 16
12
4 20
x
x
Cross Multiply, ED = 15
DC = 20 – 15 = 5x 20 – x
TOO
A
B
CDE
AB ED
BC DC
1)Given AB = 8, AC = 10, and ED = 12 Find BC, DC, and EC.
2)Given AC = 30, ED = 28, and EC = 42 Find AB, BC, and DC.
1) BC = 2 DC = 3 EC = 15
2) AB = 20 BC = 10 DC = 14
Homework
Pg 247 #1-8 all
9-27 odd
33-35 all