Reference sheet—parallel lines cut by a transversal
Angle Pair
What I need to know about the angle pair…
Alternate Exterior Angles
 On opposite sides of the transversal
 Pairs are on the outside of the parallel lines
 Angle pairs are congruent
 Angles 1 and 8; 2 and 7
What it looks like
1
7
2
8
Alternate Interior Angles




On opposite sides of the transversal
Pairs are on the inside of the parallel lines
Angle pairs are congruent
Angles 3 and 6; 4 and 5

Pairs are in the same relative location in
reference to the parallel lines
Angle pairs are congruent
Angles 1 and 5; 3 and 7; 2 and 6; 4 and 8
3
5
4
6
Corresponding Angles


1
3
5
7
Consecutive Interior Angles




On the same side of the transversal
Inside the parallel lines
Angles are supplementary ( 180 )
Angles 3 and 5; 4 and 6
2
4
6
8
3
5
4
6
Reference Sheet—Angle Pairs
Type of Angle Pair
Adjacent Angles
What I need to know about the angle pair…
 Share a common side & common vertex
What the angle pair looks like…
common side
vertex
Supplementary Angles
(a.k.a. linear pair)


Form a straight line
Angles add up to 180
Complementary Angles

Add up to 90
1
2
Angles 1 and 2 are
complementary angles
Vertical Angles


Formed by intersecting lines
Angles are across from one another
vertical angles are equal in measure/
congruent (  )
1
4
3


Perpendicular ( ) Lines


Form right angles
Right angles = 90
2
Angles 1 and 3 are vertical angles and
are equal in measure
Angles 2 and 4 are vertical angles and
are equal in measure
Reference Sheet – Angle Types
Angle Types
What I need to know about the angle types…
Acute

An acute angle is an angle whose measure
is less than 90°

An obtuse angle is an angle whose measure
is more than 90°, but less than 1800

A right angle is an angle whose measure is
90°.

A straight angle is an angle whose measure
is 180°.
Obtuse
Right
Straight
What it looks like
Reference Sheet – Classification of Triangles by Angles
Classification of Triangles By Angles
What I need to know…
Acute

An Acute Triangle has all angles measuring
less than 90°.

A Right Triangle has one right angle.
(A right angle measures exactly 90°).

An Obtuse Triangle has one angle
measuring more than 90°.
It is not possible to draw a triangle with
more than one obtuse angle.
Right
Obtuse

Equiangular



An Equiangular Triangle has 3 congruent
angles.
All angles measure the same, and each
angle measures 60°.
This triangle is the same as the equilateral
triangle.
What it looks like
Reference Sheet – Classification of Triangles by Sides
Classification of Triangles By Sides
What I need to know…
Scalene


A Scalene Triangle has no congruent
sides.
Each side in this triangle has a different
length.
Isosceles

An Isosceles Triangle has two congruent
sides.

An Equilateral Triangle has three
congruent sides.
Equilateral
What it looks like