Bellwork
Take out your homework and leave it on
your desk.
Pick up the worksheet on the little desk.
Assemble into your groups and complete
the worksheet.
Problem 1
F is complementary to G
H is complementary to G
If mF = 28, find the measure of G & H.
Which angles are congruent? Why?
Write your conclusion in conditional (if-then) form.
Problem 2
1 is complementary to 2
3 is complementary to 4
2  4
If m1 = 35, find the measures of 2,
3 and 4.
Which other set of angles is also congruent? Why?
Write your conclusion in conditional form.
Problem 3
1 is supplementary to 3
2 is supplementary to 3
If m1 = 110, find the measure of 2 & 3.
Which angles are congruent? Why?
Write your conclusion in conditional (if-then) form.
Problem 4
A is supplementary to C
B is supplementary to D
C   D
If mA = 125, find the measures of B,
C and D.
Which other set of angles is also congruent? Why?
Write your conclusion in conditional form.
Theorems: Toolbox!
We write:
2.4 Congruent Supplements
and Complements
Students will be able to apply the two
theorems regarding congruent/same
comps and supps.
Class Exercises
Turn to page 79 in your book.
What reason would you use to prove
#2?
#3?
#6?
Example 1
Given: AD  AB
AC  AE
Prove: 1  3
Example 2
Given:1 is comp to  4
 2 is comp to3
RT bisects SRV
Prove: TR bisects STV
Example 3
Given: PQR is supp to QRS
QRS is supp to TWX
PQR  (5x  48), TWX  (2 x  30)
Find: mQRS
Ticket to Leave
Write the correct theorem you would use for
the following proof:
Given:
ABC is supp to OPQ
OPQ is supp to DEF
Prove:
ABC  DEF
Homework
Pg. 79 # 1, 8, 10, 11, 12, 15, 17, 19
Quiz Tomorrow over sections 2.1-2.4
Example 2:
 Given: <FKJ is a right angle
<HJK is a right angle
<GKJ  <GJK
Conclusion: <FKG  <HJG
Bellwork
Draw a picture for and complete the proof
of a theorem below.
Given: 3 is supp to 4; 4  6
 6 is supp to 5
Prove: 3  5
Group work: You will have 7 mins!
Each group is given one proof.
Draw a picture and complete the proof.
Write the theorem in conditional form.
2 people from your group(s) will be
randomly selected to
Write the proof on the board
Explain the proof.
As people explain their proof. Write the
conclusion in your toolbox!
Bellwork
1. Review: If two sides of a triangle are 4
and 9, what is the largest integral value
for the length of the third side?
2. Review: What are the restrictions of x if
 B is acute and mB  2 x  8 ?