1-4 Measuring Segments and Angles
AB 5 in
Postulate 1-5 Ruler Postulate The point of a line can be put into a one- to-one correspondence with the real number so that the distance between any two points is the absolute value of the difference of the corresponding numbers. AB = | a – b | BA 410
Examples— A BC DE CD= BC= EB= DE=
Two segments with the same length are congruent. If AB = CD, then AB ≅ CD ≅ means congruent BA 6 BA DC 6 DC
Postulate 1-6 Segment Addition Postulate If three points A, B, and C are collinear and B is between A and C, then AB + BC = AC A B C
Write the Segment Addition Postulate for the points described. Draw a picture to help. S is between D and P C is between Q and R T is between M and N
For each problem, draw a picture representing the three points and the information given. Solve for indicated. If AC = 24 in. and CE = 13 in., AE = _____. If CE = 7in. and AE = 23 in., AC = _____.
Find QR in the following problems. R is between Q and S. If RS = 44.6 and SQ = 68.4, find QR. If RS = 33.5 and RQ = 80, find SQ.
If GJ = 32, find x find GH find HJ If AX = 45, find y find AQ find QX
For each problem, draw a picture representing the three points and the information given. Solve for indicated. Given : AC = 39 m A B C 2x-8 x+17 x = ________ AB = _______ BC = _______
If U is between T and B, find the value of x and the lengths of the segments. TU = 2x, UB = 3x + 1, TB = 21 x = ______ TU = _______ UB = _______ TU = 4x-1, UB = 2x -1, TB = 5x x = ______ TU = _______ UB = _______
A midpoint of a segment is a point that divides the segment into two congruent segments. ABC M is the midpoint of RT find x find RM find RT
An angle is formed by two rays (called sides of the angle) with the same endpoint (called the vertex of the angle). Angles are measured in degrees. Sides are GC and GA; G is the vertex. Name this angle: G 3 CGA AGC
A B D C O
Angles can be... Acute: 0 < x < 90 x° Right: x = 90 x° Obtuse: 90 < x < 180 x° Straight: x = 180
17 Adjacent Angles Two angles are called adjacent angles if they share a vertex and a common side (but neither is inside the opening of the other). Angles 1 and 2 are adjacent: 1 2
Postulate 1-8 Angle Addition Postulate If point B is in the interior of AOC, then m AOB + m BOC = m AOC.
19 Example A M T H
Angles with the same measure are congruent. If m 1 = m 2, then 1 2 Congruent “ curtains ”
Homework— Page (1, 3, 8-16, 27, 28, 59, 60, 61, , 75-78)