Use Proportions to Solve
Geometric Problems
6.2
Proportion Properties
• The Reciprocal Property:
– If two ratios are equal, then their
reciprocal is also equal.
– Basically, you can flip ratios to make new
equivalent ratios.
Examples
If
6 x
 ,
7 14
then
14 7

6
x
Proportion Properties
• If you have 2 ratios equal to each other, then
the numerators can be turned into a new ratio
and the denominators into another new ratio.
Examples
Proportion Properties cont.
• You can add the denominator of each ratio to
the numerator to get a new ratio.
Examples
True or False?
true
true
false
true
True or False?
false
true
true
true
True or False?
false
true
true
BA = 12, BD = x – 3 = 12 – 3 = 9
What do I know?
XW = 1, XY = 3, YZ = 2, and WV is unknown so
WV = x
1
3

x
2
1(2) = 3x
2 = 3x
2
x
3
SR = 3, RQ = 4, ST = 6, and TU = x
3
6

4
x
3x  6(4)
3x  24
x8
BC = x, AB = 12, CD = 24, and DE = 18
x
24

12
18
18x  12(24) 18 x  288
x  16
HI = 21, GH = 14, JK = x, and KD = 12
21
x 14x  21(12) 14 x  252 x  18

14 12
JD  JK  KD  18  12  30
Worksheet