Transcript cross products

Review
Chapter 4
Ratio and Rates
4.1
Vocabulary
• Ratio – a comparison of two numbers by
division.
• Rate – a comparison of two quantities with
different types of units
• Unit Rate – a rate that has been simplified
so it has a denominator of 1.
Rate of Change
4.2
Vocabulary
• Rate of change – a rate that describes
how one quantity changes in relation to
another.
Rate of Change
Rate of Change Graphs
Slope
4.3
Vocabulary
• Slope – the rate of change between two
points
• Rise – the vertical change
• Run – the horizontal change
Solving Proportions
4.4
Vocabulary
• Proportion – two ratios that are equivalent.
• Cross Products – the process of
multiplying two ratios for comparison or
solution.
Proportion
PROPORTION:
Cross Products
CROSS PRODUCTS:
6 3

8 4
24  24
Using Cross-Products To Solve
2 6

3 x
2 x  18
2 2
x9
Set your two proportions to be equal
Use your cross-products to set up the
equation
Multiplication problem: Divide
X equals your missing denominator!
2 6

3 9
Similar Polygons
4.5
Vocabulary
• Polygon – a simple closed figure in a plane
formed by three or more line segments
• Similar – polygons that have the same shape
• Corresponding parts – parts of similar figures
that “match”
• Congruent – angles that have the same
measure
• Scale factor – the ratio of the lengths of two
corresponding sides of two similar polygons
Properties of Similar Polygons
Similar Polygons
Scale
Scale Drawings and Models
4.6
Vocabulary
• Scale drawing – a 2 dimensional representation of an
object that is too large or too small to be drawn or built at
actual size.
• Scale Model – a 3 dimensional representation of an
object that is too large or too small to be drawn or built at
actual size.
• Scale – the ratio of the given length on a drawing or
model to its corresponding actual length.
1 inch = 4 feet
1:30 = 1 unit represents an actual distance of 30 units.
Indirect Measurement
4.7
Vocabulary
• Indirect measurement – the technique of
using properties of similar polygons and
proportions to find distances or lengths
that can be difficult to measure directly.
Shadow Reckoning
Dilations
4.8
Vocabulary
• Dilation – the image produced by
enlarging or reducing a figure
Scale Factor