Pre-Algebra Chapter 6 - Ramsey School District

Interior Designer
Interior designers plan the
space and furnish the
interiors of places such
as homes, offices,
restaurants, hotels,
hospitals, and even
theaters. Creativity and
knowledge of computeraided
design software is
essential.
Online Research
For information about
a career as an interior
designer, visit:
www.pre-alg.com/
careers
CONSTRUCT SCALE DRAWINGS To construct a scale drawing of an
object, use the actual measurements of the object and the scale to which the
object is to be drawn.
Example 3
Construct a Scale Drawing
INTERIOR DESIGN Antonio is designing a room that is 20 feet long
and 12 feet wide. Make a scale drawing of the room. Use a scale of
0.25 inch 4 feet.
Step 1 Find the measure of the room’s length on the drawing.
Let x represent the length.
Step 2
Step 3
drawing length →
actual length →
0.2 5 in
4 fe
ch
et
x inches
2
0 feet
0.25 20 4 x Find the cross products.
5 4x Simplify.
1.25 x Divide each side by 4.
On the drawing, the length is 1.25 or 1 1 4 inches.
Find the measure of the room’s width on the drawing.
Let w represent the width.
drawing length →
actual length →
0.2 5 in
4 fe
ch
et
w inches
12
feet
0.25 12 4 w Find the cross products.
3 4w Simplify.
3 4 4 4w Divide each side by 4.
0.75 w Simplify.
On the drawing, the width is 0.75 or 3 4 inch.
Make the scale drawing.
Use 1 -inch grid paper. Since
4
1 1 4
3 4
inches 5 squares and
inch 3 squares, draw a
rectangle that is 5 squares by
3 squares.
← drawing length
← actual length
← drawing length
← actual length
20 ft
12 ft
Concept Check
1. OPEN ENDED Draw two squares in which the ratio of the sides of the
first square to the sides of the second square is 1:3.
2. FIND THE ERROR Montega and Luisa are rewriting the scale
1 inch 2 feet in a:b form.
Montega
1:36
Luisa
1:24
278 Chapter 6 Ratio, Proportion, and Percent
Who is correct? Explain your reasoning.