6th Grade Math Textbook, Fundamentals

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Naples

Everglades

National Park

St. Petersburg

Miami

Key West

Cape

Kennedy

Orlando

Tampa

Daytona Beach

6-6

Scale Drawings and Models

Objective To use proportions to solve scale-drawing and scale-model problems

• To use a map scale • To use a scale factor to make a scale-model

About how many miles is St. Petersburg from Naples?

To find how many miles, use the scale drawing,

the map scale, and proportional reasoning.

A two-dimensional drawing that is in proportion to

an actual object is called a. A scale

drawing can be larger or smaller than the actual object.

The gives the ratio of the picturedmeasure, the

distance on the map, to the actualmeasure or distance.

The scale for the Florida map is 1 inch 112 miles.

This means that 1 inch on the map represents an

actual distance of 112 miles.

To find the actual distance:

• Identify the two cities on the map.


• Use an inch ruler to measure the distance
  between the two points on the map.


• Choose a variable to represent the actual distance.


• Write and solve a proportion.
  The scale distance measures 1.5 inches.
  Let dthe actual distance between
  St. Petersburg and Naples.

scale drawing

scale

Solve: 

 Cross multiply.

d1.5 • 112 Simplify.

d168 mi

It is about 168 miles from St. Petersburg to Naples.

1.5 in.

dmi

1 in.

112 mi

1.5 in.

dmi

1 in.

112 mi Check:

168  168 Tr u e

?

168 mi1.5 in.

?



1 in.

112 mi

1.5 in.

168 mi

1 in.

112 mi

scale measure

actual measure

 &KDSWHU

What is the actual length of a hallway, h, that measures

2.5 cm on a scale drawing? Use the scale at the right.

Solve:  Check:

h3 • 2.5 1 • 7.5 3 • 2.5

h7.5 7.5 7.5 Tr u e

The actual length of the hallway is 7.5 meters.

?

?2.5 cm

7.5 cm

1 cm

3 m

2.5 cm

hm

1 cm

3 m

1 Scale
1 cm 3 m

Scale

1 inch 112 miles