The document provides instruction on several geometry concepts: 1) It defines supplementary, complementary, adjacent, and vertical angles and provides examples of each. 2) It explains that the three angles of any triangle always add up to 180 degrees. 3) It illustrates a transversal bisecting parallel lines.

1. • 1. Discuss HW
• 2. Using Algebra to Solve Word Problems
• 3. Practice
• 4. Notes: Basic Geometry Concepts

2. • 1. When twice a number
is increased by one, the
result is thirteen.
• 2. Five times a number
decreased by two equals
nine.
• 3. Three less than a
number divided by eight
is six.

3. + In a row =
The sum of three consecutive numbers is 57.
Step 1: Assign Step 2: Write an
variables. You equation that show s
will need three. that the sum of the
three numbers is 57.
First number: x
Step 3: Combine like
Second number: x + 1 terms and solve the
Third number: x + 2 equation.
Step 4: To find the
other two
numbers, substitute
18 for x in the
expressions x + 1 and

4. You can use algebra to solve ratio problems.
There are twice as many women as there are men in Juanita’s Spanish class.
There are 24 students in the class. How many of the students are women?
Step 1: Assign Step 2: Write
variables. You an equation Step 4: Find the
will need two. that shows that number of
the total women.
Men= number of
Women= students is 24.
Step 3: Combine
like terms and
solve the
equation.

5. • The Millers, the Rigbys, and the Smiths went on a camping
trip. The Millers spent $100 more than the Rigbys, and the
Smiths spent twice as much as the Millers. If the cost of the
trip was $580 altogether, how much did the Smiths spend?
Step 1: Assign Step 2: Write Step 3: Combine Step 4: Find the
variables. You an equation like terms and amount the
will need 3. that shows that solve the Smiths spent.
the total dollar equation.
amount spent
•Millers = on the trip is
•Rigbys = $580.
•Smiths =

6. • Lowercase letters refer to the OPENING of
each angle.
• Uppercase letters refer to the vertex and a
point on each side of an angle.
A
D
g
f
h
O
B C

7. • Two angles that add up to 180˚ are called
supplementary angles.
C
A B
O
•∠AOB forms a straight angle. •∠AOC and ∠BOC combined measure
•Remember that a straight angle 180° and are therefore supplementary.
measures 180°

8. • Two angles that add to 90˚ are called
complementary angles.
D
•∠DEG = 50°
•∠DEF = 90°
G •Therefore, ∠GEF =
40°
Since ∠DEG and ∠GEF add
F
E up to 90°, the two angles
are complementary.

9. • Adjacent angles are two angles that share a
side.
W
Z
∠WOZ and ∠WOY
share a side WO.
O
Therefore, ∠WOZ
and ∠WOY are
adjacent angles.
Y X

10. • Vertical angles are two angles opposite
(across from) each other when two lines
intersect.
• Vertical angles are equal.
t
s u
v

11. • A line that bisects (cuts across) parallel lines.
c
a
b
d

12. a
The three angles of a + b + c = 180°
a triangle add up
to 180°. Always.
b c