Textbook Pages 430435 Objective I can solve scale drawing problems using proportions Vocabulary Scale Drawing is the same shape but not the same size A map is a scale drawing The units are very important ID: 712842
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Slide1
Proportions and Scale Drawings
Textbook Pages 430-435Slide2
Objective
I can solve scale drawing problems using proportions.Slide3
Vocabulary
Scale Drawing:
is the same shape but not the same size. A map is a scale drawing. The units are very important.
Scale:
tells us how the drawings dimensions and the actual dimensions are related. (Ratio)
The standard way to write the scale is scale model to actual object or
scale:actualSlide4
Interpreting Scale Drawing
3 inches
The scale is 1 in. : 5ft
Find the actual length of the canoe.
1in
3 in
.
5ft ?ftWhat did you do to 1 to get to 3. Multiplied by 3. So multiply 5 by 3 to get 15 ft.Slide5
Try some!
The scale of a drawing 2 in.: 6m
Length of the drawing = 8in.
Length of object = __________
Length of object = 36 m
Length of drawing = __________Slide6
Word Problems
You are building a model boat with a scale of 1 in.:2ft.
The actual boat is 18 feet long.
How long should you make your model?
9 inchesSlide7
Using it to find area and perimeter.
A scale drawing of this classroom is 2cm by 3 cm. The scale is
1cm:2m
. What is the area of the classroom?Slide8
Draw a diagram
Using the scale model 1in.:10ft, make a scale drawing of a 30ft by 40 foot dance floor.
You should have a 3in by 4 in drawing
Use your drawing to find the actual distance from opposite corners.
If you measured on your scale drawing you would find it to be 5 inches.
Using the scale it would convert to 50 ft.Slide9
Finding the scale!
A museum is creating a full sized T-Rex from a model. The model is 40 inches in length. The resulting dinosaur will be 40 feet tall in length. What is the models scale?
Write a ratio. Make sure both measures are in inches. Then simplify.
40in
=
40 in
40
ft 480 inThe model scale is 1:12Slide10
Try some:
Find the model scale:
5in
2ft
5/24
1ft
8yd
1/24Slide11
Practice
Workbook Pages
109-110
Even