LESSON 8.6 Day 1 Notes - Scale Drawings and Models

Goal: Use proportions with scale drawings.

Warm-up:

1) A blueprint is a technical drawing that usually displays architectural plans. Johnny’s blueprint shows a layout of a house. Every 4 inches in the blueprint represents 3 feet of the actual house. One of the walls in the blueprint is 24 inches long. Complete the table to find the actual length of the wall.

Blueprint length (in.) 4 8 12 16 20 24

Actual length (ft) 3 6

What is the actual length of the wall?

2) In Johnny’s blueprint the length of a side wall is 16 inches. What is the actual length of the wall?

3) The back wall of the house is 33 feet long. What is the length of the back wall in the blueprint?

4) How do you know your answer to 3 is reasonable? __________________________________________________________________________________

Vocabulary Scale Drawing: EXAMPLE:

Scale Model:

EXAMPLE:

Scale:

NOTE: IF THE SCALE IS USING DIFFERENT UNITS, THE UNITS MUST BE STATED.

EXAMPLE 1 - Using the Scale of a Map Use the map of Nebraska to estimate the distance between the towns of Ogallala and Central City.

Now You Try It! Use a metric ruler and the map in Example 1

1. Calculate the distance, in miles, between the towns of Alliance and Geneva.

EXAMPLE 2 – Using a Scale Model

The following is a floor plan of a library.

Write and solve proportions to find the Actual Dimensions of the Check-Out area.

Actual dimensions:

2

EXAMPLE 3 - Using a Scale Drawing to Find Area

The figure is a scale drawing of a large rectangular room. What is the area of the actual room? Set up proportions to help you solve the problem.

A) What information do you need before you can find the area of a rectangle? B) What information do we still need before we can find the area of the actual room? Perform those calculations.

C) What is the area of the actual room?

NOW YOU TRY IT!

1) Find the area of the actual room. Round your answer to the nearest tenth.