lesson (6.5) parts of similar triangles bc a d altitude bc a n median angle bisector bc a m
TRANSCRIPT
Lesson (6.5) Parts of Similar Triangles
B C
A
D
Altitude
B C
A
N
Median Angle bisector
B C
A
M
E F
D
X
Y
Z
B C
A
M
L
N ~
DE
AB EF
BC FD
CA DX
AM EY
BN FZ
CL DEFofperimeter
ABCofperimeter
If then
The perimeter of the triangle is the sum of the measures of its sides
Angle bisector Theorem
B C
A
D
If AD is an
angles bisector then
DC
BD AC
BA
Check for understandingCheck for understanding
Find the perimeter of the given triangle
37,6,5,~, DEandACBCABDEFABCifDEF
• Step1: Set up proportions.
• Step3: Cross multiply and solve for x.
x
18
3
5 545 x
5 58.10x
DE
AB EF
BC FD
CA DEFofperimeter
ABCofperimeter
• Step2: substitute the values.
3
5 EF
6 FD
7 x
18
Check for understandingCheck for understanding
Find x
• Step1: Set up proportions.
• Step2: Cross multiply and solve for x.
13
5.6
12
x 7813 x 13 13
6x
12
x 13
5.6
Check for understandingCheck for understanding
Find x
• Step1: Set up proportions.
• Step2: Cross multiply and solve for x.
3
420
x604 x
4 415x
x
20 12
16
Check for understandingCheck for understanding
Find x
• Step1: Use the angle bisector Theorem.
• Step2: Cross multiply and solve for x.
8
3
18
x 548 x 8 8
75.6x
18
x 24
9
HomeworkHomeworkHomeworkHomework
Page 320 – 322
#s (10, 14, 18, 22, 24)
Written Exercises page 320Written Exercises page 320
Find the perimeter of the given triangle
84,5,12,~, DEandFEFDCDFDEBCDifBCD
• Step1: Set up proportions.
• Step3: Cross multiply and solve for x.
• Step2: substitute the values.
10)
Written Exercises page 320Written Exercises page 320
Find the perimeter of the given triangle
5,3,4,~, CBandDBCDCBDABCifABC
• Step1: Set up proportions.
• Step3: Cross multiply and solve for x.
• Step2: substitute the values.
14)
Written Exercises page 320Written Exercises page 320
5.7
,15,17,
,~
EHand
ADACEGFofalttitudeanisEH
ACBofalttitudeanisADEGFACBifEGfind
• Step1: Set up proportions.
• Step3: Cross multiply and solve for x.
• Step2: substitute the values.
18)
Find x
• Step1: Set up proportions.
• Step2: Cross multiply and solve for x.
Written Exercises page 321Written Exercises page 321
22)
Find x
• Step1: Use the angle bisector Theorem.
• Step2: Cross multiply and solve for x.
Written Exercises page 321Written Exercises page 321
24)