Day Measuring Segments and Angles

Day Measuring Segments and AnglesMonday 2/4

Warm-Up 2/4/20131. Name the Intersection of Plane AED and HEG.2. Name the fourth point in the

plane BCH.3. Use always, sometimes, or never

to made a true statement: a) Three points are ? Coplanar.b) Two lines ? Meet in more than

one point.

Homework Check

Measuring Segments and Angles

Find KNEX:

7 13KN = distance between K and N or the length

of KN

= the name of the segment between K and N

Find a length or distance on a number line =

K N

Congruent Segments: segments that are the same length.

J

K

M

L

Segment Addition Postulate: If A, B, and C are collinear and B is between A and C

Then AB + BC = AC

A

CB

Midpoint of a segment

On a # line:

The midpoint splits the segment in exactly half!

Segment Bisector: A figure that passes through the midpoint of a segment.

J

K

S

T

Examples: 1. W is between V and X, VW = 3x+5,

WX=2x+10 and VX = 50. Find VW.

V XW

2. K is the midpoint of . JK = 2x+1 and KL=3x-4. Find JL.

1-4 Measuring Angles

Angle: is formed by two rays with the same endpoint.

The rays are the SIDES of the angle. The endpoint is the VERTEX of the angle.

EX NAMES: <ABC<CBA<1

Protractor Postulate

m<COD =

Acute Angle

Measures greater than and less than

Right Angle

Measures exactly

Obtuse Angle

Measures greater than and less than

Straight Angle

Measures exactly

Adjacent Angles

Angles that are beside each other and share a common ray as one of their sides.

______ and _______ are adjacent angles.

Linear PairAre adjacent angles whose non-

common sides are opposite rays.

Opposite Rays:A Linear Pair is:

**If two angles are a linear pair, then their sum is

m<ABD + m<DBC = 180

Congruent Angles

Are angles that have the same measure.

Angle Addition Postulate

Angle BisectorIs a ray that divides an angle into two

angles.

____ bisects _______, therefore_____________

Examples:1.

2.

3.

HW: Complete the worksheet1-4