Beginning Angles Lesson

Beginning Angles

Parts of the ANGLES

• Angles are formed by 2 rays or lines that meet at a single point called a vertex.

• Rays are like the rays of the sun; they start at some point in the sun and shoot out (infinitely) forever in 1 direction.

• Lines continue in opposite directions Infinitely (forever).

Multiple Choice

This is the point where 2 rays meet to form an angle.

• vertex

• angle

• arc

• corner

There are 4 names of ANGLES based on their measure.

• ACUTE angles are angles that have measures between 0 and 90 degrees.

• RIGHT angles have exactly 90 degrees.

• OBTUSE angles have measures between 90 and 180 degrees.

• STRAIGHT angles have exactly 180 degrees.

Multiple Choice

An angle that measures less than 90°

• Acute

• Obtuse

• Right

• Straight

Multiple Choice

This is what kind of angle?

• right

• acute

• obtuse

• straight

Multiple Choice

What type of angle is shown?

• acute

• obtuse

• right

• straight

Multiple Choice

Which type of angle is pictured?

• Acute

• Right

• Obtuse

• Straight

2 types of angles are classified by what they share.

• ADJACENT ANGLES share a side, line, or ray. Think of the letter T as being like upside-down L's sharing a long side.

• VERTICAL ANGLES share a vertex only. Think of the letter X as being 2 V's that share a vertex.

• Because VERTICAL ANGLES are created when 2 lines cross at an intersection (the vertex) they are always opposite of each other and their measures are always equal.

Multiple Choice

Which are pairs of vertical angles?

• ∠COB & ∠COA

• ∠AOD & ∠AOC

• ∠COB & ∠AOD

• ∠BOD & ∠AOD

Multiple Choice

Vertical angles are always

• acute

• total 180 degrees

• congruent (equal measures)

• adjacent angles

Multiple Choice

What type of angles are next to each other and share a side?

• vertical

• supplementary

• complementary

• adjacent

2 types of angles are classified by what they create when combined together.

• COMPLEMENTARY ANGLES are combined to add up to 90 degrees; together, they make a right angle.

• SUPPLEMENTARY ANGLES are combined to add up to 180 degrees; together, they make a straight angle.

Multiple Choice

What are complementary angles?

• Angles that add up to 180°
• Angles that add up to 90°
• Angles that are equal to each other
• Angles that are opposite of each other when lines intersect.

Multiple Choice

What kind of angles are shown?

• complementary

• supplementary

• adjacent

• corresponding

Multiple Choice

What are supplementary angles?

• Angles that add up to 180°
• Angles that add up to 90°
• Angles that are equal to each other
• Angles that are opposite of each other when lines intersect

Multiple Choice

Are these angles complementary, supplementary, or neither?

• Complementary

• Supplementary

• Neither

Multiple Select

Which are pairs of supplementary angles? Check all that apply.

• ∠COB & ∠COA

• ∠AOD & ∠AOC

• ∠COB & ∠AOD

• ∠BOD & ∠AOD