1. Scale Drawing/Scale Models
Scale Drawings & Models are used to represent objects that are too large or too small to be drawn or built at actual size
Examples:
RC Cars, Atlas, Insects… others?

2. Scale
Gives the ratio that compares the measurements of the drawing or model to the measurements of the real object.
They are proportional.
ex. – map scale

3. You try it…
Find the actual distance if the map scale is inches = 30 miles
2 inches =
x = 15 miles
Use CMAD (cross multiply and divide) to solve this proportion. First, multiply 2 inches and 30 miles for a product of 60. Then, divide 60 by 4 for a quotient of 15. Note: students will get the same answer if they first simplify 4 inches : 30 miles to 2 inches : 15 miles before they CMAD.

4. How can you use this?
A scale drawing of a rectangular room has a length
of 6 inches and a width of 4 inches.
The drawing uses a scale of one inch to three feet.
1. How many square feet is the room?
2. How much will it cost to carpet the room if
carpeting costs $5.50 per square foot?
There are two methods for solving problem #1. Students could either convert the measurements from the scale drawing into the actual dimensions of a length of 18 feet and a width of 12 feet, then use the formula for finding the area of a rectangle (A=lw) to find the area, or they could square the scale and find that the scale of the area of the rectangle is 1 sq in : 9 sq ft, then set the scale equal to the ratio of the area of the scale drawing (6 inches x 4 inches = 24 sq in). Either process will give the answer as 216 square feet. Using the price of $5.50 per square foot, the answer to #2 is $1,188.
216 ft2
216 ft2 x $5.50 = $1,188

5. What do they look like? REPLICA (an exact copy of the original)
REDUCTION (from original to smaller)
ENLARGEMENT (from original to larger)

6. What’s the difference? SCALE SCALE FACTOR
Gives a ratio that compares measurements
Does not have to be in the same units
EX 1 inch : 5 feet
It’s a scale, but it must have the same units, and is in simplest form
You might have to convert the units
EX 1 inch : 5 feet (scale) CONVERT both to inches ;
1 inch : 60 inches = 1:60 scale factor
SCALE
SCALE FACTOR