Parallel Lines and Transversals Prerequisite

Parallel Lines and Transversals Prerequisite

What is an angle?

• A figure formed by two rays meeting at a common end point called a vertex

Angles can be named several ways

• Use the vertex and a point from each side. The vertex letter is always in the middle.

•  $\angle SRT\ or\ \angle TRS$  

Angles can be named several ways

• Use the vertex vertex only

•  $\angle R$  

• If there is only one angle at the vertex, the the angle can be named with that vertex

Angles can be named several ways

• Use a number if provided

•  $\angle1$  

Angle Measures

• Once the measure of the angle is known, the angle can be classified as one of 3 types of angles.

• Obtuse Angle: An angle greater than

   $90\degree$  

• Acute Angle:  An angle less than  $90\degree$  

• Right Angle:  An angle that is  $90\degree$  

Multiple Choice

An obtuse angle measures:

• Less than 90 degrees

• Greater than 90 degrees

• 90 degrees

Multiple Choice

An acute angle measures:

• 90 degrees

• Greater than 90 degrees

• Less than 90 degrees

Multiple Choice

Which one is a right angle?

Multiple Choice

Which type of angle is this?

• Acute

• Obtuse

• Right

Multiple Choice

Which type of angle is this?

• Acute

• Obtuse

• Right

Adjacent Angles

• Two angles are Adjacent when they have a common side and a common vertex

Open Ended

Name a pair of adjacent angles.

Complementary Angles

• Two angles that together, the sum of the angles is equal to

   $90\degree$  

Supplementary Angles

• If the sum of the measure of two angles is:

   $180\degree$ 

Multiple Choice

Find the missing angle

• x = 118

• x = 108

• x = 28

• x = 58

Multiple Choice

Find the missing angle.

• 60°

• 70°

• 50°

• 140

Multiple Choice

Are these angles complementary, supplementary or neither?

• complementary

• supplementary

• neither

Vertical Angles

• When two lines intersect, four angles are formed

• There are two pairs of NON-adjacent angles

• These pairs are called vertical angles

• Vertical angles are congruent (same angle measure)

Open Ended

What is the value of x?

Multiple Choice

If the measure of ∠2 is 83°, what is the measure of ∠3?

• 7°

• 17°

• 83°

• 97°

Multiple Choice

∠1 and ∠3 can best be described as -

• complementary angles

• supplementary angles

• vertical angles

• adjacent angles

Multiple Choice

What kind of angles are shown?

• complementary

• supplementary

• adjacent

• corresponding