6-3: Scale Drawings
Problem of the Day
1) Find the Length of the missing side.
5-8: Scale Drawings and Scale Models
Making comparisons and finding dimensions of scale drawings, models, and actual objects
Vocabulary
Scale Drawing
A two dimensional drawing that is used to represent an object that is too large or small to be drawn at actual size
(blue prints, maps, assembly instructions, etc.).
Scale Model
A three dimensional object that is used to represent an object that is too large or small to be drawn at actual size
(model cars, model buildings).
Vocabulary
Scale
The ratio of the dimensions in a drawing to the dimensions of the actual object.
Vocabulary
Scale
The ratio of the dimensions in a drawing to the dimensions of the actual object.
Ex: The scale on map may be 1 in: 10 miles, 1 in to 10 miles, or 1 inch
10 miles
Vocabulary
Scale Factor
The ratio of a length on a scale drawing or model to the corresponding length on the real object is called the scale factor
Vocabulary
Scale Factor
The ratio of a length on a scale drawing or model to the corresponding length on the real object is called the scale factor.
Example
Scale model has a scale of 2 inches = 4 feet. To find the scale factor, set up a ratio and convert to same units….
Vocabulary
Scale Factor
The ratio of a length on a scale drawing or model to the corresponding length on the real object is called the scale factor.
Example
Scale model has a scale of 2 inches = 4 feet. To find the scale factor, set up a ratio and convert to same units….
2 in
4 feet
2 in
48 in
1 in
24 in
Vocabulary
Scale Factor
The ratio of a length on a scale drawing or model to the corresponding length on the real object is called the scale factor.
Example
Scale model has a scale of 2 inches = 4 feet. To find the scale factor, set up a ratio and convert to same units….
2 in
4 feet
2 in
48 in
1 in
24 in
1
The scale factor is … The drawing is the size of
24 the actual object
1
24
Vocabulary
A scale drawing or model that is smaller than the actual object is called a Reduction . A scale drawing or model that is larger than the object is called an Enlargement .
Steps in Solving
To find the missing length of an actual object using a given scale…
I.
Write a proportion using the given scale; setting it equal to the given actual size and the missing measurement.
II. Be sure to place corresponding units across from each other.
Examples
A model of a 27 ft. tall house was made using a scale of 2 in: 3 ft. What is the height of the model?
Under a 1,000:1 microscope view, an amoeba appears to have a length of 8 mm.
What is its actual length?
Problems/Examples of
A) The length of an object on a scale drawing is 2 cm, and its actual length is 8 m. The scale is 1 cm: _______ m. What is the scale?
B) What is the scale of a drawing in which a 9 ft. wall is 6 cm long?
Problems/Examples of
Find the Scale Factors
C) 1 in.: 4 ft.
D) 2 ft.: 6 in.
E) 2 ft.: 30 yd
Problems/Examples of
4 scale, how long would a drawing of a 22 ft. car be?
G) The height of a person on a scale drawing is 4.5 in.
The scale is 1:16. What is the actual height of the person?
Problems/Examples of
Tell whether each scale reduces, enlarges, or preserves the size of an actual object.
J. 50 ft.: 1 in.
H. 10 ft. : 24 in.
K.
0.2 in: 2 ft
I. 1 mi: 5,280 ft.
Now try these…
1) A map has a scale of 1 inch = 8 miles. two towns are 3.25 inches apart on the map.
What is the actual distance between the two towns?
Now Try These…
1) A map has a scale of 1 inch = 8 miles. Two towns are 3.25 inches apart on the map.
What is the actual distance between the two towns?
1 inch
3 .
25 inches
8 miles Xmiles x = (3.25)(8 miles) x = 26 miles
Now Try These…
2) A map has a scale of 1 inch = 8 miles. two towns are 3.25 inches apart on the map.
What is the scale factor?
Now Try These…
2) A map has a scale of 1 inch = 8 miles. two towns are 3.25 inches apart on the map.
What is the scale factor?
3 .
25 inches
26 miles
Now Try These…
2) A map has a scale of 1 inch = 8 miles. two towns are 3.25 inches apart on the map.
What is the scale factor?
3 .
25 inches
26 miles
3 .
25 inches
1 , 647 , 360 inches
1 inch
506 , 880 inches
Now Try These…
3) A model car is 4 inches long. The actual car is 12 feet long. What is the scale of the model?
Now Try These…
3) A model car is 4 inches long. The actual car is 12 feet long. What is the scale of the model?
4
inch
1
inch
12
feet xfeet
Now Try These…
3) A model car is 4 inches long. The actual car is
12 feet long. What is the scale of the model?
4 inch
1 inch
12 feet xfeet
4x =12 x = 3
Now Try These…
3) A model car is 4 inches long. The actual car is 12 feet long. What is the scale of the model?
4
inch
1
inch
12
feet xfeet
4x =12 x = 3
1 inch
3 feet or 1 inch = 3 feet
