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Segment Measure and Coordinate Graphing. Chapter 2. Real Numbers and Number Lines. Section 2-1. NATURAL NUMBERS - set of counting numbers. {1, 2, 3, 4, 5, 6, 7, 8…}. WHOLE NUMBERS – set of counting numbers plus zero. {0, 1, 2, 3, 4, 5, 6, 7, 8…}. INTEGERS –
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Segment Measure and Coordinate Graphing Chapter 2
Real Numbers and Number Lines Section 2-1
NATURAL NUMBERS - set of counting numbers {1, 2, 3, 4, 5, 6, 7, 8…}
WHOLE NUMBERS – set of counting numbers plus zero {0, 1, 2, 3, 4, 5, 6, 7, 8…}
INTEGERS – set of the whole numbers plus their opposites {…, -3, -2, -1, 0, 1, 2, 3, …}
RATIONAL NUMBERS - numbers that can be expressed as a ratio of two integers a and b and includes fractions, repeating decimals, and terminating decimals
EXAMPLES OFRATIONAL NUMBERS 0.375 = 3/8 0.66666…= 2/3 0/5 = 0
IRRATIONAL NUMBERS - numbers that cannot be expressed as a ratio of two integers a and b and can still be designated on a number line
REAL NUMBERS Include both rational and irrational numbers
Coordinate • The number that corresponds to a point on a number line
AbsoluteValue • The number of units a number is from zero on the number line
Segments and Properties of Real Numbers Section 2-2
Betweeness • Refers to collinear points • Point B is between points A and C if A, B, and C are collinear and AB + BC = AC
Example • Three segment measures are given. Determine which point is between the other two. • AB = 12, BC = 47, and AC = 35
Measurement and Unit of Measure • Measurement is composed of the measure and the unit of measure • Measure tells you how many units • Unit of measure tells you what unit you are using
Precision • Depends on the smallest unit of measure being used
Greatest Possible Error • Half of the smallest unit used to make the measurement
Percent Error Greatest Possible Error x 100 measurement
Congruent Segments Section 2-3
Congruent Segments • Two segments are congruent if and only if they have the same length
Theorems • Statements that can be justified by using logical reasoning
Theorem 2-1 • Congruence of segments is reflexive
Theorem 2-2 • Congruence of segments is symmetric
Theorem 2-3 • Congruence of segments is transitive
Midpoint • A point M is the midpoint of a segment ST if and only if M is between S and T and SM = MT
Bisect • To separate something into two congruent parts
The Coordinate Plane Section 2-4
Coordinate Plane • Grid used to locate points • Divided by the y-axis and the x-axis into four quadrants • The intersection of the axes is the origin
An ordered pair of numbers names the coordinate of a point • X-coordinate is first in the ordered pair • Y-coordinate is second in the ordered pair
Postulate 2-4 • Each point in a coordinate plane corresponds to exactly one ordered pair of real numbers. Each ordered pair of real numbers corresponds to exactly one point in a coordinate plane.
Theorem 2-4 • If a and b are real numbers, a vertical line contains all points (x, y) such that x = a, and a horizontal line contains all points (x, y) such that y = b.
Midpoints Section 2-5
Theorem 2-5Midpoint formula for a line • On a number line, the coordinate of the midpoint of a segment whose endpoints have coordinate a and b is a+b. 2
Theorem 2-6Midpoint formula for a Coordinate Plane • On a coordinate plane, the coordinates of the midpoint of a segment whose endpoints have coordinates (x1, y1) and (x2, y2) are (x1 + x2 , y1 + y2) 2 2