Download Intro to Congruent Figures

12/5: Identify congruent figures & their corresponding congruent
parts
Do Now
On your desk:
Agenda
Homework
Announcements
Handout
- Pencil & Calculator
- Handouts from front
Guided Practice
Do Now:
Write
objective in
notes
Independent Practice
Exit Ticket
(15 problems)
Test
Corrections will
replace Exam
Retakes
We will learn to…
Identify congruent figures & their corresponding
congruent parts
Vocabulary
size
shape
Congruent figures have the same _______
& _______
• Their corresponding parts (matching _______
sides and
angles ) are _________________.
congruent
_________
Congruent Figures
• Their corresponding parts are congruent, meaning:
sides
length
o Matching _______have
the same ________
angles
measure
o Matching _______have
the same degree
________
Example 1: Naming Congruent Parts of Congruent Figures
Angles:
∠E ≅ ∠S
∠D ≅ ∠R
∠F ≅ ∠T
Sides:
𝑬𝑫 ≅ 𝑺𝑹
𝑬𝑭 ≅ 𝑺𝑻
𝑫𝑭 ≅ 𝑹𝑻
∆EDF ≅ ∆SRT
Triangle Congruence Statement: _________________
vertices in the same order
 Must list corresponding ___________
Example 2: Naming Congruent Parts of Congruent Figures from a
Congruence Statement
If HIJK≅LMNO, list the congruent corresponding parts.
Angles:
∠H ≅ ∠L
∠I ≅ ∠M
∠J ≅ ∠N
∠K ≅ ∠O
Sides:
𝑯𝑰 ≅ 𝑳𝑴
𝑰𝑱 ≅ 𝑴𝑵
𝑱𝑲 ≅ 𝑵𝑶
𝑯𝑲 ≅ 𝑳𝑶
Example 3: Using Congruent Figures to Solve for Missing Values
LM = GH
8 = 2x – 3
11 = 2x
x = 5.5
∠N ≅ ∠E
72 = 7y + 9
63 = 7y
9=y
Example 4: Check your understanding by completing alone! 
Given that ∆XYZ ≅ ∆RST, find the value of a.
∠Y ≅ ∠S
4a – 4 = 48
4a = 52
a = 13
Check Your Understanding!
1. Write a triangle congruence statement for the two
triangles below:
FGH ≅ Δ_______
JKH
Δ_______
Check Your Understanding!
2. If you are given that ∆AUS ≅ ∆KAP, name the three
pairs of congruent sides.
𝑨𝑼 ≅ 𝑲𝑨
𝑼𝑺 ≅ 𝑨𝑷
𝑨𝑺 ≅ 𝑲𝑷
Third Angles Theorem
angles of one triangle are __________
congruent to
two _______
If _____
two angles of ________
third
another triangle, then the ______
angles are _________.
congruent
_______
Example 4: Using the Third Angles Theorem
∠M ≅ ∠T
m∠M = m∠T
92⁰ = m∠T
180 – (52 + 36)
180 - 88
92⁰
Example 6: Applying the Third Angles Theorem
Find the value of x.
x = 15
Your Independent Practice Time
• Prepare for ET
– Complete HW due 12/7(A) and 12/8(B)
• Can you answer these questions:
– What is the Third Angles Theorem used for?
showing two angles are congruent
– How do you write a congruence statement?
use vertices in correct order
– What do we mean by congruent corresponding parts?
sides and angles