Geometry: Angle Measures

Do Now:What is the distance between R and Q?

What is the distance between S and R?

Homework

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Struggles?

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Definitions: Angle: An angle is formed by

two non-collinear rays that have a common endpoint.

Sides: The rays are the sides of the angle

Vertex: The endpoint is called the vertex of the angle.

Ex:

Example One:

Example Two:

Which angles have R as a vertex?

What are the sides of <1?

What is another name for <SRP?

Angles- Four Types

Obtuse Angles: Are greater than 90 degrees but less than 180 degrees.

Ex:

Angles- Four Types

Acute Angles: Are less than 90 degrees

Ex:

Angles- Four Types

Right Angles: 90 degree angles

Denoted by a little square.

Ex:

Angles- Four Types

Straight Angles: 180 degree angle

i.e. a straight line.

EX:

Protractors Steps to measuring an angle:

Line up the vertex with the center point of the protractor.

Line up the zero line on the protractor with one side of the angle.

Extend the other side of the angle using a ruler or straight edge if needed.

Wherever the other side of the angle hits the protractor is the measure of your angle!

Using Protractors

Protractor Practice

Protractor Practice

Try the other two on your own!

Congruent Angles

Congruent Lengths are…..

So…. Congruent angles are……?

Notation:

Definition

Segment Addition Postulate says what….?

So…. Angle addition postulate says:

Ex:

Example Three:

Example Four

Practice Problems

Try some angle things on your own!

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