SCALE DRAWING, PERIMETER, AREA, AND VOLUME

 

 

Unit Overview 

 

In this unit you will learn how measurement can help make life run smoothly.  You will learn to use formulas to help you compute area, perimeter, and volume.  You will learn how to read and interpret a scale drawing.

 

 

 

Perimeter 

 

The perimeter is the distance around a figure and is measured in plain units (in., yd., ft., etc.)  To find the perimeter of a straight edged figure, add all the sides.

 

 

 

 

 

 

 

Scale Drawing 

 

A scale drawing is a drawing that represents a real object. The drawing may be a reduction or an enlargement. For our purposes, we will consider a scale drawing to be a reduction. A real life scale drawing could be a blueprint of a building, a house, or more commonly, a map of the United States. 

 

Each scale drawing has its own scale ratio. A scale ratio represents the drawing measurement compared to the real measurement. For example on a map it is possible that 1/2 inch represents 200 actual miles. This ratio is then used to find other aspects of the scale drawing.  

 

Let’s take a look at an example. The illustration below represents the plans for a backyard. The scale for the drawing is 1/4 inch = 8 feet.

 

 

 

 

 

 

 

 

 

 

 

 

Area

 

The area of a two-dimensional figure is the amount of space on the surface of the figure and is measured in square units (in2, ft2, yd2, etc.).  There are formulas that are used to find the area of different shapes. The table below illustrates the different formulas.

 

 

 

 

 

 

Sometimes you are asked to find the area of odd-shaped figures. If this is the case, you need to divide the figure into familiar shapes and use the given formulas.

 

 

 

 

Sometimes you are asked to find the area of objects that are missing some parts. In this case, find the area of the entire figure, and then subtract the area of the missing figure.

 

 

 

 

 

 

 

Volume

 

Volume refers to the amount of space inside a three-dimensional figure and is measured in cubic units (ft3,yd3,cm3,etc.).  For our purposes, we will focus on finding the volume of a rectangular prism that has a length, width, and height as the figure below illustrates.

 

 

 

 

 

 



Below are additional educational resources and activities for this unit.
 
Unit 10 Area and Perimeter of Irregular Shapes Worksheet
 
Unit 10 Volume and Surface Area of 3D Shapes Worksheet