Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the...

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Angles

Transcript of Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the...

Page 1: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Angles

Page 2: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Angle and PointsAn Angle is a figure formed by two rays with a

common endpoint, called the vertex.

vertex

ray

rayAngles can have points in the interior, in the exterior or on the angle.

E is in the exterior.

A

BC

DE

Points A, B and C are on the angle.

D is in the interior

B is the vertex.

Page 3: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Naming an Angle

ABC or CBA Using 3 points: Vertex must be the middle letter

This angle can be named as

Using 1 point: Using only vertex letter

A

BC

B

Using a number: 2

2

Use the notation m2, meaning the measure of 2.

Page 4: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Example

K

32

K

L

M

P

Therefore, there is NO in this diagram.

Name all the angles in the diagram below

, ,LKM PKM and LKP

2 3 5!!!There is also and b Nut t Ohere is

K is the vertex of more than one angle.

Page 5: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Example

Name the three angles in the diagram.

Page 6: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

4 Types of Angles

Acute Angle: an angle whose measure is less than 90.

Right Angle: an angle whose measure is exactly 90 .

Obtuse Angle: an angle whose measure is between 90 and 180.

Straight Angle: an angle that is exactly 180 .

Page 7: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Angle Addition PostulateSame idea as the segment addition postulate

R

M K

W

The sum of the two smaller angles will always equal the measure of the larger angle.

Complete:

m ____ + m ____ = m _____MRK KRW MRW

Postulate:

Page 8: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Example

Fill in the blanks. m < ______ + m < ______ = m <

_______

Page 9: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Adding Angles

If you add m1 + m2, what is your result?

22°

36°

21

D

B

C

A

Therefore, mADC = 58.

m1 + m2 = mADC

m1 + m2 = 58.

Also…

Page 10: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Example

R

M K

W

3x + x + 6 = 90 4x + 6 = 90 – 6 = –64x = 84x = 21

K is interior to MRW, m MRK = (3x), m KRW = (x + 6) and mMRW = 90º. Find mMRK.

3xx+6

Are we done?

mMRK = 3x = 3•21 = 63º

First, draw it!

Page 11: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

ExampleGiven that m< LKN = 145, find m < LKM and m < MKN

Page 12: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

ExampleGiven that < KLM is a straight angle, find m < KLN and m < NLM

Page 13: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Example

Given m < EFG is a right angle, find m < EFH and m < HFG

Page 14: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Angle Bisector

An angle bisector is a ray in the interior of an angle that splits the angle into two congruent angles.

5

3

Page 15: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

3 5.

Congruent Angles

5

3

Definition: If two angles have the same measure, then they are congruent.

Congruent angles are marked with the same number of “arcs”.

Page 16: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

j41°

41°

64

U

K

is an angle bisectorUK

Example:

J

T

Which two angles are congruent?

<JUK and < KUT or < 4 and < 6

Page 17: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Example:Given bisects < XYZ and m < XYW = . Find m < XYZYW

??????????????18

Page 18: Angles. Angle and Points An Angle is a figure formed by two rays with a common endpoint, called the vertex. vertex ray Angles can have points in the interior,

Example:Given bisects < ABC. Find m < ABC

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