Mind on Math

• Complete the “Work Together” in your note packet with your partner.

Measuring Anglesand Segments

Geometry

Mr. Zampetti

Unit 1, Day 6

Fifth Basic Postulate

1-5: The points of a line can be put into a one-to-one correspondence with the real numbers so that the distance between any two points is the absolute value of the difference of the corresponding numbers.

Example

• Find QS (“the length of segment QS”) if the coordinate (“location”) of Q is –3 and the coordinate of S is 21.

213

24

24

Definition

Congruent: Two segments with the same length. ()

http://hotmath.com/hotmath_help/topics/congruent-segments/congruent-segments.gif

Sixth Basic Postulate

1-6: If three points A, B, and C are collinear and B is between A and C, then

AB + BC = AC.

A

B

C

Example

• If DT = 60, find the value of x. Then find DS and ST.

D S T

2x - 8 3x - 12

Definition

Angle: formed by two rays with a common endpoint (“vertex”).

C

A

B Name this angle 3 different ways.

Parts of an Angle

Sides

Vertex

Types of Angles

• Acute–Less than 90°

• Right–Exactly 90°

• Obtuse–Greater than 90°, but

less than 180°

Types of Angles

• Straight–Exactly 180°

• Reflex–Greater than 180

but less than 360

Angle Addition Postulate

If point B is in the interior of AOC, then mAOB + mBOC = mAOC

O C

BA

Example

• mHAT = 50 and mHAM = 125. What is the mMAT?

A H

TM

Homework

Homework Packet:

Measuring Angles and Segments