number talk in chemistry class there is a girl to boy ratio of 5 : 8. if there are a total of 39...
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Number Talk
In Chemistry Class there is a girl to boy ratio of 5 : 8. If there are a total of 39 students, how many boys are there?
The scale on a map is 6cm : 2kn. If the distance between two cities is 8kn, how far apart in cm are the two cities on the map?
In Geometry Class, the girl to boy ratio is 8 to 6. If there are a total of 42 students, how many girls are there?
How did we do?
Postulate 25
Angle-Angle (AA) Similarity Postulate
If two angles of one triangle are congruent to two angles of another triangle, then the two triangles are similar.
Similar Triangles Given the triangles are similar. Find the value of the
variable.
)
)
))
))11
68
m
6
118
m
11m = 48
11
48m
Let’s Try
Warm Up: Determine whether the triangles are similar.
18
9
6
32°33°
No, because two angles of one triangle are not congruent to two angles of another triangle.
Determine whether the triangles are similar.
60°
Yes, because two angles of one triangle are congruent to two angles of another triangle.
60°
60°
60°
Given two triangles are similar, solve for the variables.
15
10
16
3
a
15
115a
10
a + 3 141516
2b - 8
)
)
15(a+3) = 10(16)15a + 45 = 16015a = 115
3
23a
Decide whether two triangles are similar, not similar, or cannot be
determined.
92° 57°
92°
41°
A
A + 92 + 57 = 180A + 149 = 180 A = 31
31°S
S + 92 + 41 = 180 S + 133 = 180 S = 47
47°
Not similar
Good Afternoon – Agenda
Number Talk Discuss Overlapping Triangles Warm Up Partners Begin assignment (will finish tomorrow)
Number Talk
A child can run 4 blocks in 2 minutes. How long does it take the child to run 12 blocks?
A child can run at a rate of 2 1/2 blocks per minutes. How long does it take the child to run 7 blocks?
Similar Triangles Given the triangles are similar. Find the value of
the variable.
>
>
6
2
5
h
Left side of sm Δ Base of sm ΔLeft side of lg Δ Base of lg Δ=
h
5
8
6
6h = 40
6
40h
3
20h
∆ABC is similar to ∆DBE.
9
48
5
x
y
B
A
C
D
E
Sit in groups from last week!
2 Practice Problems
For each problem. Show your solutions mathematically as well as explain what you did in plain English.
For Example “When setting up the proportion 4/x = 15/5 I
knew that EB corresponds with DC and EA corresponds with AD.”
Discuss Yesterday’s Problems
Number Talk
What is 40 divided by 1/2, plus 15?
Number Talk
Jasmine has a toaster with two slots that toasts one side of each piece of bread at a time, and it takes one minute to do so. If she wants to make 3 pieces of toast, what is the least amount of time she needs to toast them on both sides?
Warm Up
Get Into Partners and answer this question
Identify the similar triangles. Then find each measure
Identify the similar triangles. Then find each measure
Quiz Time
6th Period : 37118705097th Period: 9841870510
