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