tuesday, august 13th

TUESDAY, AUGUST 13TH

Identify each shape

1. H is between I and J.JI = 25 and IH = 13. Find HJ. _____ 2. Find each measurement

HOMEWORK ANSWERS Please ask if you have

questions!

ANGLE EXPLORATION

Need: Paper Protractor Lined

sheet of paper

Angle measure Sheet 1 Sheet 2

<ABC

<ABD

<DBC

DISCUSSION7. What did you notice about the measure of <ABC?

8. What was the relationship between measures of <ABC, <ABD, and <DBC?

Always 90˚ m<ABD + m<DBC=m<ABC

PART 1: NAMING ANGLES

An angle is a figure formed by two rays, or sides, with a common endpoint called the vertex (plural: vertices).

You can name an angle several ways: 1. by its vertex2. by a point on each ray and the vertex3. by a number.

The set of all points between the sides of the angle is the interior of an angle. The exterior of an angle is the set of all points outside the angle.

Angle NameR, SRT, TRS, or 1

A surveyor recorded the angles formed by a transit (point A) and three distant points, B, C, and D. Name three of the angles.

Possible answer:

BAC

CAD

BAD

Example 1

Write the different ways you can name the angles in the diagram.

RTQ, T, STR, 1, 2

Example 2

PART 2: MEASURING ANGLES

The measure of an angle is usually given in degrees. Since there are 360° in a circle, one degree is of a circle. When you use a protractor to measure angles, you are applying the following postulate.

PRACTICE! Draw 2 angles and measure

with your protractor!

Congruent angles are angles that have the same measure. In the diagram, mABC = mDEF, so you can write ABC DEF. This is read as “angle ABC is congruent to angle DEF.” Arc marks are used to show that the two angles are congruent.

Reminder!

PART 3: CONSTRUCTING ANGLES

http://www.youtube.com/watch?v=YphAYfe6J40

EXAMPLE #1- LET’S TRY TOGETHER!

Use your notes from Friday!!!!

“sharp point” = Bullseye end of compass

EXAMPLE #2- YOU TRY!

Use your notes from Friday!!!!

“sharp point” = Bullseye end of compass

PRACTICE A WORKSHEET

Homework