2­5 Solving Proportions.notebook
October 11, 2016
2­5 ~ Solving Proportions
A ratio is a fraction relating two quantities. A proportion is an equation that states that two ratios are equal to each other. Using multiplication to simplify a proportion leads to what is known as "Cross Multiplication" or "solving with cross products." This property can be used to solve a proportion for a variable.
Cross Products Property of Equality:
Solve for m.
Solve each proportion using the Cross Products Property of Equality.
2­5 Solving Proportions.notebook
October 11, 2016
2­5 Solving Proportions.notebook
October 11, 2016
Proportions can be used to estimate populations using sampling
Tag and Release Population Estimates
The Wisconsin DNR tagged 1500 deer state wide. Next they observed from various lookout points. They saw 6551 deer, but only 7 were observed with tags. How many deer should the DNR estimate are in the state of Wisconsin?
Proportions and Similar Figures
Similar figures have the same shape but not necessarily the same size. Such figures can help you measure real­world distances indirectly. In similar figures, corresponding angles are equal, and the ratios of corresponding side lengths are equal.
D
A
10
12
18
15
B
8
C
E
12
F
ABC is similar to DEF because the ratios of corresponding sides are all equal. Corresponding sides:
Corresponding angles:
2­5 Solving Proportions.notebook
October 11, 2016
Use proportions to find the missing side lengths.
8
10
16
r
The scale map is .5 cm = 2 ft. What are the dimensions of the bathroom?
How tall is the tree?