Download - Monday, January 9 th
Monday, January 9th • Please complete the warm up and write
down your homework
Warm UpFind the missing value in each
pair of similar shapes1. 2.5
2
x
6
3x
10
4
Corny Joke of the Day
Why did the teacher have to wear sunglasses to
school?
Her students were too BRIGHT
What? Checkpoint #1 Similar figures
Indirect measurement
When? TODAYYYYYYYY
Week Schedule Monday: Scale Drawings NOTES
HW Scale Drawing Worksheet/Weekly Review
Tuesday: Class PROJECT HW STUDY GUIDE
Wednesday: Revie HW STUDY
Thursday: Test HW NONE
Friday: WEEKLY REVIEW DUE, Test Corrections, Translations NOTES
HW NONE
Weekly Review
Due Friday! Remember to show your work on a
separate sheet of paper
What Did Tigger do wrong?
A.B.
A and B are similar. Find y
7 14
4 x7 14
456 7
8
x
FlashcardsIndirect measurement
What is It?Indirect Measurement uses
similar figures and proportions to find height of objects you cannot
measure directly
Checkpoint Please put your name on it
Make sure to READ each question carefully
Be sure to show your work
Put in front bin when finished
Complete Weekly Review
Attention! Pezzino Travel Company
needs your help!
They need some expert map readers to find distances
between famous landmarks
First you must learn how to
interpret scale drawings!
I Spy
The map shown is a scale drawing.
A scale drawing is a drawing of a real object that is proportionally smaller or larger than the real object.
In other words, measurements on a scale drawing are in proportion to the measurements of the real object.
BUZZ WORD #1
BUZZ WORD #2
A scale is a ratio between two sets of measurements.
In the map above, the scale is 1 in:100 mi. This ratio means that 1 inch on the map represents 100 miles.
SETTING IT UP
Set up a proportion: ratio equals ratio
Scale
factor
Ratio #1 is the scale factor they give you
(first 2 numbers)
Scale scale
factor factor
Ratio #2 place third number according to measurement
Measurements match in numerators
Measurements math in denominators
Examples
in in
ft ft
ft ft
miles miles
Is it set up right?Why or why not?
1. The scale on the map is 3 cm: 10 m. On the map the distance between two cities is 40 cm. What is the actual distance?
2. The scale on the map is 10 in: 50. On the map the distance between two schools is 30 in. What is the actual distance?
3 10
40 x
10 30
50 x
Problem #1 Let’s Try Together!
The scale on a map is 4 in: 1 mi. On the map, the distance between two towns is 20 in. What is the actual
distance?
20 in. x mi
_____ 4 in. 1 mi
____ =
1 • 20 = 4 • x
20 = 4x
20 4
___ 4x 4
___ =
5 = x
Write a proportion using the scale. Let x be the actual number of miles between the two towns.
The cross products are equal.
x is multiplied by 4.
Divide both sides by 4 to undo multiplication.
5 miles
Problem #2 Let’s Try Together!
18 in. x mi
_____ 3 in. 1 mi
____ =
1 • 18 = 3 • x
18 = 3x
18 3
___ 3x 3
___ =
6 = x
Write a proportion using the scale. Let x be the actual number of miles between the two cities.
The cross products are equal.
x is multiplied by 3.
Divide both sides by 3 to undo multiplication.
6 miles
The scale on a map is 3 in: 1 mi. On the map, the distance between two cities is 18 in. What is the
actual distance?
Problem #3 You Try!
The scale on a map is 2 in: 50 mi. On the map, the distance
between two lakes is 12 in. What is the actual distance?
Problem #4 Astronomy
If a drawing of the planets was made using the scale 1 in:30 million km, the distance from Mars to Jupiter on the drawing would be about 18.3
in. What is the actual distance between Mars to Jupiter?
18.3 in. x million km
_________ 1 in. 30 million km
___________ =
30 • 18.3 = 1 • x
549 = x
Write a proportion. Let x be the actual distance from Mars to Jupiter.
The cross products are equal.
The actual distance from Mars to Jupiter is about 549 million km.
Problem #5 Rafting
Our class decides to go white-water rafting on the river. The map we have of the river has a scale of 3 inches equals 10 miles. On the map, the
distance between their start point and end point is 18 inches. What is the actual distance in
miles?
Write a proportion. Let x be the actual distance between start to end
3 18
10
in in
miles x
Solve for x180 3
60
x
x
Can you Answer the
EQ?Double time 2 minutes to answer it
2 minutes to share with elbow partner
2 minute discuss with class