Scale

Drawings

Scale Drawing: a reduced or enlarged two-dimensional drawing of an original two-dimensional drawing. 

 

 

 

For the following problems, (a) is the actual picture and (b) is the scale drawing. Is the scale drawing an enlargement or a reduction of the actual picture?

Enlargement Reduction

Height LengthOriginal Drawing

Second Drawing

Celeste drew an outline of a building for a diagram she was making and then drew a second one mimicking her original drawing.  Fill out the table and determine if the second image is a scale drawing of the original image.  

Original Second Drawing18 units 6 units

9 units 3 units

Yes, because it has a constant ratio. The constant of proportionality between the two drawings is  because the second drawing is  the size of the original.. 

a. If the original lengths are multiplied by 2, what are the new coordinates?

b. Use the table to the right to organize the lengths.

c.  Is the new picture a reduction or an enlargement?

d.  What is the constant of proportionality?  Length HeightActual Picture Lengths (in units)

   

New Picture Lengths (in units)

   

Try this one!

(0,0), (12,18), (12,0)

6 units 9 units

12 units 18 units

Enlargement

2

Use a Scale Factor of 3 to create new dimensions to make a scale drawing of the Flag of Columbia below. 

1inches

inch

inch

inch

Length: in.

Yellow width in.

Blue width in. Red width in.

A drawing of a surfboard in a catalog shows its length as 8 inches. Find the actual length of the surfboard if 1/2 inch length on the drawing corresponds to 3/8 foot of actual length.

• Hint:  Making a ratio table will help

scale equivalent scale ratio surfboard

Scale Drawing Length, x

Actual Length, y ?

 = 

y = 34

𝟑𝟒6

13

Area

Scale factor from first object to second: _________

Actual Area = ______________ 

 

         Scale Drawing Area = ________________

 

Ratio of Scale Drawing Area to Actual Area:  _________

13

54 square units

6 square units

=

Finding the ScaleA museum is creating a full-size Tyrannosaurus Rex for a model. The model is 40 inches in length, from the nose to the tail. The resulting dinosaur will be 40 feet in length. What is the model’s scale?

SolutionWrite a ratio with the model on top and the full size on bottom. Make sure that both measures are in inches. Then simplify the fraction.

feet

inches

40

40

inches

inches

480

40= =12

1 scale modelfull size

The model’s scale is or 1:12

• 1) Find the scale factor of the blueprint of a school bus parking lot if the scale is written as 1 inch = 8 feet

• 2) On a scale drawing of a new classroom, the scale is 1 centimeter = 2 meters.  What is the scale factor? (There are 100 cm in 1 meter)

1:96

1: 250

Practice:

Scale Drawing Day 1 worksheet