Scale Drawings & Models

What you will learn:Use scale drawings

Construct scale drawings

Vocabulary• Scale drawing/scale model: represent

an object that is too large or too small to be drawn

Scale

Scale: relationship between the measurements on the drawing and the real object

Example:1 inch = 3 feet

(One inch represents an actual distance of 3 feet)

Scale Factor

Scale factor: the ratio of a length on a scale drawing to the length on the real object

Example: If a scale model has a scale of 2 inches = 16 inches. The scale factor is 2 or 1 16

8The lengths and widths of objects of a scale

drawing or model are proportional to the lengths and widths of the actual object.

Example 1: Find Actual

MeasurementsA set of landscape plans shows a flower bed

that is 6.5 inches wide. The scale on the plans is 1 inch = 4 feet.

What is the width of the actual flower bed?

Example 3: Construct a Scale Drawing

A garden is 8 feet wide by 16 feet long. Make a scale drawing of the garden that has a scale of 1 in. = 2ft.

4Step 1: Find the measure of the garden’s length on the

drawing. Let x represent the length.

On the drawing, the length is 2 inches

• Step 2: Find the measure of the garden’s width on the drawing. Let w represent the width.

Your Turn!

On a set of architectural drawings for an office building, the scale is 1/2” = 3 feet. Find the actual length of each room.

Lobby: 2 inches

Cafeteria: 8.25 inches

Your Turn, Again!

In an illustration of a honey bee, the length of the bee is 4.8 cm. The actual size of the honeybee is 1.2 cm. What is the scale of the drawing?

4.8 cm = 1cm1.2 cm x cm 4.8x = 1.2 x = .25

The scale of the drawing is 1 cm = .25cm