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13Scale Down, Scale Up Unit
CMath Vo abulary scale: a proportion used to represent actual distances on a map
scale drawing: a drawing that is proportionally smaller or larger than what it represents
Have students use the scale on the map to find the actual distances of specified locations. 1. Have students solve these problems.
1 . Solve each word problem using the scale drawing. 1a is very similar to the sample problem, only
a. The distance between New York and Philadelphia is represented by a
straight line that is 3 cm on the map. What is the actual distance in miles?
a different part of the US. 1b differs only in the
scale, which is very much larger than typical
geographical maps or even city road maps.
As with the sample problem, formal errors in
setting up these problems can lead to
scale confusion, and as shown in the sample,
0 30 60 miles
“marking off” distances along the map and
serve as a clarifying device.
1 cm = 30 miles Confusion can be avoided by keeping mental
1 = 3 1 a = 30 3 focus on the unit of scale.
30 a
a = 90 Refer to .
90 miles
b. The distance between the school and the post office is represented by a
straight line that is 4 cm on the map. What is the actual distance in meters?
fast-food
restaurant
school
library post
office
scale
0 200 400 meters
1 cm = 200 m
1 = 4 1 a = 200 4
200 a a = 800
800 m
13. Scale Down, Scale Up 111
Working successfully with scales depends largely on grasping the unit of scale and interpreting it as unity.
For this reason the actual overall scale of the map (e.g., 1 : 1,000,000) is often less emphasized than the
reference unit (on that scale, 1 cm 10 km).
This is especially true for traditional Anglo-American measurement units – for example, a map with the
awkward-sounding scale 1 : 63,360 corresponds to 1 inch 1 mile.
For scale drawings, the reference unit is often listed by itself, for example “quarter-inch scale” means a
quarter inch equates to one foot (1 : 48).
6A Unit 13 185
13Scale Down, Scale Up Unit
CMath Vo abulary scale: a proportion used to represent actual distances on a map
scale drawing: a drawing that is proportionally smaller or larger than what it represents
Have students use the scale on the map to find the actual distances of specified locations. 1. Have students solve these problems.
1 . Solve each word problem using the scale drawing. 1a is very similar to the sample problem, only
a. The distance between New York and Philadelphia is represented by a
straight line that is 3 cm on the map. What is the actual distance in miles?
a different part of the US. 1b differs only in the
scale, which is very much larger than typical
geographical maps or even city road maps.
As with the sample problem, formal errors in
setting up these problems can lead to
scale confusion, and as shown in the sample,
0 30 60 miles
“marking off” distances along the map and
serve as a clarifying device.
1 cm = 30 miles Confusion can be avoided by keeping mental
1 = 3 1 a = 30 3 focus on the unit of scale.
30 a
a = 90 Refer to .
90 miles
b. The distance between the school and the post office is represented by a
straight line that is 4 cm on the map. What is the actual distance in meters?
fast-food
restaurant
school
library post
office
scale
0 200 400 meters
1 cm = 200 m
1 = 4 1 a = 200 4
200 a a = 800
800 m
13. Scale Down, Scale Up 111
Working successfully with scales depends largely on grasping the unit of scale and interpreting it as unity.
For this reason the actual overall scale of the map (e.g., 1 : 1,000,000) is often less emphasized than the
reference unit (on that scale, 1 cm 10 km).
This is especially true for traditional Anglo-American measurement units – for example, a map with the
awkward-sounding scale 1 : 63,360 corresponds to 1 inch 1 mile.
For scale drawings, the reference unit is often listed by itself, for example “quarter-inch scale” means a
quarter inch equates to one foot (1 : 48).
6A Unit 13 185
